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Results for “Cell Surface Extensions”

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At least 109 records · Page 6Linked to original sources

PubMed1999

The actin cytoskeleton reorganization induced by Rac1 requires the production of superoxide.

The small GTPase rac1 controls actin redistribution to membrane ruffles in fibroblasts and other cell types, as well as the activation of the NADPH oxidase in phagocytes. We explored the possibility that these two processes could be related. We used a replication-deficient adenoviral vector to overexpress the constitutively active form of rac1, racV12, in human and mouse aortic endothelial cells. We show here that, in addition to membrane ruffle formation, racV12 induced an increase in the total amount of F-actin within endothelial cells. Concurrently, racV12-overexpressing cells produced significantly higher amounts of free radicals, as detected by the fluorescent probe 5-(and-6)-chloromethyl-2',7'-dichloro-dihydrofluorescein diacetate, than cells infected with a control virus encoding the bacterial beta-galactosidase (Ad-betaGal). To assess the specific role of superoxide in racV12-induced actin reorganization, we co-expressed the human enzyme Cu,Zn-superoxide dismutase (SOD), by means of another adenoviral vector construct. Overexpressed SOD reduced the concentration of superoxide detected in Ad-racV12-transfected cells and reversed the effects of Ad-racV12 on the content of filamentous actin. MnTMPyP, an SOD mimetic, as well as the antioxidant N-acetyl cysteine, had similar effects, in that they reduced not only the free radicals production, but also ruffle formation and the concentration of F-actin within racV12-overexpressing endothelial cells. Our data support the hypothesis that superoxide is one of the important mediators acting downstream of rac1 on the pathway of actin cytoskeleton remodeling in endothelial cells.

Acetylcysteine↗

PubMedDate not supplied

Influence of culture method on the proliferation and osteogenic differentiation of human adipo-stromal cells in nonwoven fabrics.

The initial attachment, proliferation, and osteogenic differentiation of stromal cells from human fat tissue were investigated in three-dimensional nonwoven fabrics prepared from polyethylene terephthalate (PET) fiber with different diameters. The largest number of cells initially attached was observed in the nonwoven fabrics prepared from PET fiber with a diameter of 22.0 microm, irrespective of fabric porosity. The number of cells attached was larger and the cells were distributed more homogeneously in the fabrics by the agitated seeding method than by the static seeding method. The culture method depended on the time profile of cell proliferation. Cell proliferation improved in the following order: stirred (spinner flask) culture method > agitated culture method > static culture method. In addition, cells proliferated homogeneously in fabrics by the stirred culture method. When evaluated as a measurement of cell osteogenic differentiation, the activity of alkaline phosphatase (ALP) was not influenced by the diameter of fabrics. The static culture method tended to enable cells to enhance ALP activity, in contrast with the stirred and agitated culture methods. It is concluded that fabric fiber diameter and culture method greatly affected the proliferation and differentiation of cells in nonwoven fabrics.

Adipocytes↗

PubMed2003

Extracellular ATP causes ROCK I-dependent bleb formation in P2X7-transfected HEK293 cells.

The P2X7 ATP receptor mediates the cytotoxic effect of extracellular ATP. P2X7-dependent cell death is heralded by dramatic plasma membrane bleb formation. Membrane blebbing is a complex phenomenon involving as yet poorly characterized intracellular pathways. We have investigated the effect of extracellular ATP on HEK293 cells transfected with the cytotoxic/pore-forming P2X7 receptor. Addition of ATP to P2X7-transfected, but not to wt P2X7-less, HEK293 cells caused massive membrane blebbing within 1-2 min. UTP, a nucleotide incapable of activating P2X7, had no early effects on cell shape and bleb formation. Bleb formation triggered by ATP was reversible and required extracellular Ca2+ and an intact cytoskeleton. Furthermore, it was completely prevented by preincubation with the P2X blocker oxidized ATP. It was recently observed that the ROCK protein is a key determinant of bleb formation. Preincubation of HEK293-P2X7 cells with the ROCK blocker Y-27632 completely prevented P2X7-dependent blebbing. Although ATP triggered cleavage of the ROCK I isoform in P2X7-transfected HEK293 cells, the wide range caspase inhibitor z-VAD-fluoromethylketone had no effect. These observations suggest that P2X7-dependent plasma membrane blebbing depends on the activation of the serine/threonine kinase ROCK I.

Adenosine Triphosphate↗

PubMed2002

Continual production of phosphatidic acid by phospholipase D is essential for antigen-stimulated membrane ruffling in cultured mast cells.

Phospholipase Ds (PLDs) are regulated enzymes that generate phosphatidic acid (PA), a putative second messenger implicated in the regulation of vesicular trafficking and cytoskeletal reorganization. Mast cells, when stimulated with antigen, show a dramatic alteration in their cytoskeleton and also release their secretory granules by exocytosis. Butan-1-ol, which diverts the production of PA generated by PLD to the corresponding phosphatidylalcohol, was found to inhibit membrane ruffling when added together with antigen or when added after antigen. Inhibition by butan-1-ol was completely reversible because removal of butan-1-ol restored membrane ruffling. Measurements of PLD activation by antigen indicate a requirement for continual PA production during membrane ruffling, which was maintained for at least 30 min. PLD1 and PLD2 are both expressed in mast cells and green fluorescent protein-tagged proteins were used to identify PLD2 localizing to membrane ruffles of antigen-stimulated mast cells together with endogenous ADP ribosylation factor 6 (ARF6). In contrast, green fluorescent protein-PLD1 localized to intracellular vesicles and remained in this location after stimulation with antigen. Membrane ruffling was independent of exocytosis of secretory granules because phorbol 12-myristate 13-acetate increased membrane ruffling in the absence of exocytosis. Antigen or phorbol 12-myristate 13-acetate stimulation increased both PLD1 and PLD2 activity when expressed individually in RBL-2H3 cells. Although basal activity of PLD2-overexpressing cells is very high, membrane ruffling was still dependent on antigen stimulation. In permeabilized cells, antigen-stimulated phosphatidylinositol(4,5)bisphosphate synthesis was dependent on both ARF6 and PA generated from PLD. We conclude that both activation of ARF6 by antigen and a continual PLD2 activity are essential for local phosphatidylinositol(4,5)bisphosphate generation that regulates dynamic actin cytoskeletal rearrangements.

ADP-Ribosylation Factor 1↗

PubMed2003

Betacap73-ARF6 interactions modulate cell shape and motility after injury in vitro.

To understand the role that ARF6 plays in regulating isoactin dynamics and cell motility, we transfected endothelial cells (EC) with HA-tagged ARF6: the wild-type form (WT), a constitutively-active form unable to hydrolyze GTP (Q67L), and two dominant-negative forms, which are either unable to release GDP (T27N) or fail to bind nucleotide (N122I). Motility was assessed by digital imaging microscopy before Western blot analysis, coimmunoprecipitation, or colocalization studies using ARF6, beta-actin, or beta-actin-binding protein-specific antibodies. EC expressing ARF6-Q67L spread and close in vitro wounds at twice the control rates. EC expressing dominant-negative ARF6 fail to develop a leading edge, are unable to ruffle their membranes (N122I), and possess arborized processes. Colocalization studies reveal that the Q67L and WT ARF6-HA are enriched at the leading edge with beta-actin; but T27N and N122I ARF6-HA are localized on endosomes together with the beta-actin capping protein, betacap73. Coimmunoprecipitation and Western blot analyses reveal the direct association of ARF6-HA with betacap73, defining a role for ARF6 in signaling cytoskeletal remodeling during motility. Knowledge of the role that ARF6 plays in orchestrating membrane and beta-actin dynamics will help to reveal molecular mechanisms regulating actin-based motility during development and disease.

ADP-Ribosylation Factor 6↗

PubMed2003

Asymmetric distribution of myosin IIB in migrating endothelial cells is regulated by a rho-dependent kinase and contributes to tail retraction.

All vertebrates contain two nonmuscle myosin II heavy chains, A and B, which differ in tissue expression and subcellular distributions. To understand how these distinct distributions are controlled and what role they play in cell migration, myosin IIA and IIB were examined during wound healing by bovine aortic endothelial cells. Immunofluorescence showed that myosin IIA skewed toward the front of migrating cells, coincident with actin assembly at the leading edge, whereas myosin IIB accumulated in the rear 15-30 min later. Inhibition of myosin light-chain kinase, protein kinases A, C, and G, tyrosine kinase, MAP kinase, and PIP3 kinase did not affect this asymmetric redistribution of myosin isoforms. However, posterior accumulation of myosin IIB, but not anterior distribution of myosin IIA, was inhibited by dominant-negative rhoA and by the rho-kinase inhibitor, Y-27632, which also inhibited myosin light-chain phosphorylation. This inhibition was overcome by transfecting cells with constitutively active myosin light-chain kinase. These observations indicate that asymmetry of myosin IIB, but not IIA, is regulated by light-chain phosphorylation mediated by rho-dependent kinase. Blocking this pathway inhibited tail constriction and retraction, but did not affect protrusion, suggesting that myosin IIB functions in pulling the rear of the cell forward.

Actins↗

PubMed2003

The eps8 family of proteins links growth factor stimulation to actin reorganization generating functional redundancy in the Ras/Rac pathway.

Sos-1, a guanine nucleotide exchange factor (GEF), eps8 and Abi1, two signaling proteins, and the lipid kinase phosphoinositide 3-kinase (PI3-K), assemble in a multimolecular complex required for Rac activation leading to actin cytoskeletal remodeling. Consistently, eps8 -/- fibroblasts fail to form membrane ruffles in response to growth factor stimulation. Surprisingly, eps8 null mice are healthy, fertile, and display no overt phenotype, suggesting the existence of functional redundancy within this pathway. Here, we describe the identification and characterization of a family of eps8-related proteins, comprising three novel gene products, named eps8L1, eps8L2, and eps8L3. Eps8Ls display collinear topology and 27-42% identity to eps8. Similarly to eps8, eps8Ls interact with Abi1 and Sos-1; however, only eps8L1 and eps8L2 activate the Rac-GEF activity of Sos-1, and bind to actin in vivo. Consistently, eps8L1 and eps8L2, but not eps8L3, localize to PDGF-induced, F-actin-rich ruffles and restore receptor tyrosine kinase (RTK)-mediated actin remodeling when expressed in eps8 -/- fibroblasts. Thus, the eps8Ls define a novel family of proteins responsible for functional redundancy in the RTK-activated signaling pathway leading to actin remodeling. Finally, the patterns of expression of eps8 and eps8L2 in mice are remarkably overlapping, thus providing a likely explanation for the lack of overt phenotype in eps8 null mice.

Actins↗

PubMed2005

Ena/VASP proteins can regulate distinct modes of actin organization at cadherin-adhesive contacts.

Functional interactions between classical cadherins and the actin cytoskeleton involve diverse actin activities, including filament nucleation, cross-linking, and bundling. In this report, we explored the capacity of Ena/VASP proteins to regulate the actin cytoskeleton at cadherin-adhesive contacts. We extended the observation that Ena/vasodilator-stimulated phosphoprotein (VASP) proteins localize at cell-cell contacts to demonstrate that E-cadherin homophilic ligation is sufficient to recruit Mena to adhesion sites. Ena/VASP activity was necessary both for F-actin accumulation and assembly at cell-cell contacts. Moreover, we identified two distinct pools of Mena within individual homophilic adhesions that cells made when they adhered to cadherin-coated substrata. These Mena pools localized with Arp2/3-driven cellular protrusions as well as at the tips of cadherin-based actin bundles. Importantly, Ena/VASP activity was necessary for both modes of actin activity to be expressed. Moreover, selective depletion of Ena/VASP proteins from the tips of cadherin-based bundles perturbed the bundles without affecting the protrusive F-actin pool. We propose that Ena/VASP proteins may serve as higher order regulators of the cytoskeleton at cadherin contacts through their ability to modulate distinct modes of actin organization at those contacts.

Actin Cytoskeleton↗

PubMed2006

Plasma membrane sterol distribution resembles the surface topography of living cells.

Cholesterol is an important constituent of cellular membranes. It has been suggested that cholesterol segregates into sterol-rich and -poor domains in the plasma membrane, although clear evidence for this is lacking. By fluorescence imaging of the natural sterol dehydroergosterol (DHE), the lateral sterol distribution has been visualized in living cells. The spatial labeling pattern of DHE coincided with surface structures such as ruffles, microvilli, and filopodia with correlation lengths in the range of 0.8-2.5 microm. DHE staining of branched tubules and of nanotubes connecting two cells was detected. Dynamics of DHE in folded and plane membrane regions was comparable as determined by fluorescence recovery after photobleaching. DHE colocalized with fluid membrane-preferring phospholipids in surface structures and at sites of cell attachment as well as in the cleavage furrow of dividing cells, but it was not particularly enriched in those regions. Fluorescent sterol showed homogeneous staining in membrane blebs induced by F-actin disruption. Cross-linking the ganglioside GM1--a putative raft marker--did not affect the cell surface distribution of DHE. The results suggest that spatial heterogeneities of plasma membrane staining of DHE resolvable by light microscopy reflect the cell surface topography but not phase-separated sterol domains in the bilayer plane.

Actins↗

PubMed2002

The essential oil secretory structures of Prostanthera ovalifolia (Lamiaceae).

The structure of the essential oil secretory tissues of Prostanthera ovalifolia R.Br was investigated using bright- and dark-field optical microscopy, and scanning and transmission electron microscopy. The leaves of P. ovalifolia have glandular trichomes of the peltate type common to many Lamiaceae species. The trichomes consist of a basal cell embedded in the epidermis, a stalk cell with heavily cutinized walls and a 16-celled secretory head, but they differ from those of many previously reported Lamiaceae species in their morphological form defined by the elevated cuticle. The sub-cuticular space contains a mixture of lipid and aqueous phases. Secretory cells have dense cytoplasm with many leucoplasts present. Volatile terpenoids are eliminated from the cytoplasm into the sub-cuticular space, the site of essential oil accumulation, via granulocrine secretion.

Cell Surface Extensions↗

PubMed2003

UV-induced blue-green and far-red fluorescence along wheat leaves: a potential signature of leaf ageing.

Under UV-excitation, leaves emit red (RF) and far-red (FRF) fluorescence from chlorophyll and blue-green fluorescence (BGF) from hydroxycinnamic acids. In this study, the aim was to develop a fluorescence signature of wheat leaf ageing after the emergence of the lamina. FRF and BGF were examined in the first three leaves of 2-week-old wheat plants. It was investigated how FRF and BGF vary as leaf and tissue aged by spectroscopic measurements, time-resolved BGF analysis and microscopic imaging of the leaf surface. It was found that FRF decreased with leaf and tissue ageing because of an accumulation of UV-absorbers in the epidermis. BGF also decreased, but without changes either in the shape of excitation and emission spectra or in the fluorescence lifetime. So, BGF emanated from the leaf surface, without changes in fluorophore composition during leaf ageing. The shape of the BGF spectrum indicates that ferulic acid bound to the cell wall is the main blue-green fluorophore. The effects of pH and solvents on BGF from intact leaves and ferulic acid in solution were similar, confirming the hydroxycinnamic acid origin of BGF. UV-fluorescence microscopic imaging of the surface of intact leaves showed that different epidermis cell types and sclerenchyma bands emitted BGF. The decreasing gradient of BGF from the base to the apex of the lamina could be related to the decrease in the surface of the fluorescent sclerenchyma bands. The significance of FRF and BGF as potential signatures of wheat lamina growth are discussed.

Apoptosis↗

PubMed2002

Rhizoid differentiation in Spirogyra: position sensing by terminal cells.

Some species of Spirogyra anchor themselves to the substrate by differentiating rhizoids. A rhizoid is differentiated only from the terminal cell, suggesting that this cell can recognize its terminal position in a filament. In the present study, we have analyzed the mechanism for position sensing by the terminal cell. When a filament is cut, a new cell occupies the terminal position, and three phenomena are induced: (1) the cell wall of the cut cell detaches from the new terminal cell; (2) adhesive material is secreted by the terminal cell; and (3) the terminal cell begins to differentiate a rhizoid via tip growth. All of these phenomena were inhibited by adding sorbitol to the external medium, suggesting that turgor pressure is involved in position sensing by the terminal cell. The inhibition by sorbitol was reversible. Upon cutting a filament, the distal end of a new terminal cell became convex. However, when a filament was cut in the presence of sorbitol, the distal end of a new terminal cell became less convex. Either treatment with Gd(3+) or decrease in extracellular Ca(2+) resulted in inhibition of all these phenomena, suggesting possible involvement of stretch-activated ion channel in position sensing by terminal cells.

Calcium↗

PubMed2002

Salicylic acid carboxyl methyltransferase induced in hairy root cultures of Atropa belladonna after treatment with exogeneously added salicylic acid.

In Atropa belladonna hairy roots, exogeneously added salicylic acid (SA) is converted to methyl salicylate (MSA) through the reaction, which might be catalysed by S-adenosyl-L-methionine: salicylic acid carboxyl methyltransferase (SAMT). Here we cloned a cDNA for A. belladonna SAMT (AbSAMT1), which consisted of 357 aa residues. It was expressed in E. coli, and the recombinant AbSAMT1 showed SAMT activity. When A. belladonna hairy roots were exposed to a high concentration of SA, AbSAMT1 mRNA begins to be expressed 12 h after the exposure, and steady expression continued over 144 h.

Amino Acid Sequence↗

PubMed2001

NMDA receptors mediate hypoxic spine loss in cultured neurons.

We examined the pharmacology of dendritic morphologic changes in cultured cortical neurons exposed to sublethal oxygen-glucose deprivation (OGD). Confocal analysis of DiI-labeled neurons demonstrated transient dendritic swelling and spine loss after OGD. These morphological changes were reproduced by direct application of NMDA, kainate, veratridine, ionomycyin, and gramicidin, but not KCl. Blockade of voltage-gated sodium or calcium channels did not prevent OGD-induced dendritic spine loss. In contrast, the NMDA receptor antagonist, MK-801, fully prevented these changes. An AMPA/kainate receptor antagonist, NBQX, had no effect by itself but reduced spine loss when added to MK-801. While alterations in dendrite morphology may be triggered by activation of disparate ion channels, rapid spine loss in hypoxic cortical neurons is mediated preferentially through activation of the NMDA subtype glutamate receptor.

Animals↗

PubMed2002

Isolation and characterization of a novel ribosome-inactivating protein from root cultures of pokeweed and its mechanism of secretion from roots.

Ribosome-inactivating proteins are N-glycosidases that remove a specific adenine from the sarcin/ricin loop of the large rRNA, thus arresting protein synthesis at the translocation step. In the present study, a novel type I ribosome-inactivating protein, termed PAP-H, was purified from Agrobacterium rhizogenes-transformed hairy roots of pokeweed (Phytolacca americana). The protein was purified by anion- and cation-exchange chromatography. PAP-H has a molecular mass of 29.5 kD as detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and its isoelectric point was determined to be 7.8. Yeast (Saccharomyces cerevisiae) ribosomes incubated with PAP-H released the 360-nucleotide diagnostic fragment from the 26S rRNA upon aniline treatment, an indication of its ribosome-inactivating activity. Using immunofluorescence microscopy, PAP-H was found to be located in the cell walls of hairy roots and root border cells. PAP-H was determined to be constitutively secreted as part of the root exudates, with its secretion enhanced by a mechanism mediated by ethylene induction. Purified PAP-H did not show in vitro antifungal activity against soil-borne fungi. In contrast, root exudates containing PAP-H as well as additional chitinase, beta-1,3-glucanase, and protease activities did inhibit the growth of soil-borne fungi. We found that PAP-H depurinates fungal ribosomes in vitro and in vivo, suggesting an additive mechanism that enables PAP-H to penetrate fungal cells.

Amino Acid Sequence↗

PubMed2003

The MUR3 gene of Arabidopsis encodes a xyloglucan galactosyltransferase that is evolutionarily related to animal exostosins.

Xyloglucans are the principal glycans that interlace cellulose microfibrils in most flowering plants. The mur3 mutant of Arabidopsis contains a severely altered structure of this polysaccharide because of the absence of a conserved alpha-L-fucosyl-(1-->2)-beta-D-galactosyl side chain and excessive galactosylation at an alternative xylose residue. Despite this severe structural alteration, mur3 plants were phenotypically normal and exhibited tensile strength in their inflorescence stems comparable to that of wild-type plants. The MUR3 gene was cloned positionally and shown to encode a xyloglucan galactosyltransferase that acts specifically on the third xylose residue within the XXXG core structure of xyloglucan. MUR3 belongs to a large family of type-II membrane proteins that is evolutionarily conserved among higher plants. The enzyme shows sequence similarities to the glucuronosyltransferase domain of exostosins, a class of animal glycosyltransferases that catalyze the synthesis of heparan sulfate, a glycosaminoglycan with numerous roles in cell differentiation and development. This finding suggests that components of the plant cell wall and of the animal extracellular matrix are synthesized by evolutionarily related enzymes even though the structures of the corresponding polysaccharides are entirely different from each other.

Amino Acid Sequence↗

PubMed2005

Rapid WAVE dynamics in dendritic spines of cultured hippocampal neurons is mediated by actin polymerization.

The Wiskott-Aldrich syndrome protein family Verprolin-homologous protein (WAVE) complex has been proposed to link Rho GTPase activity with actin polymerization but its role in neuronal plasticity has never been documented. We now examined the presence, distribution and dynamics of WAVE3 in cultured hippocampal neurons. WAVE3 was localized to dendritic spines via its N-terminal domain. Green fluorescent protein (GFP)-tagged WAVE3 clusters demonstrate an F-actin-dependent high rate of local motility. Constitutive Rac activation translocates WAVE3 (via the N-terminus), to the leading edge of lamellipodia. Also, spinogenesis is associated with actin-based motility of the WAVE3 protein. Brain specific WAVE1 showed similar localization and effects on spine density. Cytoplasmic fragile X mental retardation protein interacting protein (CYFIP) and non-catalytic region of tyrosine kinase adaptor protein 1 (NCK-1), proteins that are assumed to complex with WAVE, have a somewhat similar cellular distribution and motility. We propose that the WAVE complex is a downstream effector of the Rac signaling cascade, localized to sites of novel synaptic contacts by means of its N-terminal domain, to guide local actin polymerization needed for morphological plasticity of neurons.

2-Amino-5-phosphonovalerate↗

PubMedDate not supplied

Novel type of interstitial cell (Cajal-like) in human fallopian tube.

We describe here--presumably for the first time--a Cajal-like type of tubal interstitial cells (t-ICC), resembling the archetypal enteric ICC. t-ICC were demonstrated in situ and in vitro on fresh preparations (tissue cryosections and primary cell cultures) using methylene-blue, crystal-violet, Janus-Green B or MitoTracker-Green FM Probe vital stainings. Also, t-ICC were identified in fixed specimens by light microscopy (methylene-blue, Giemsa, trichrome stainings, Gomori silver-impregnation) or transmission electron microscopy (TEM). The positive diagnosis of t-ICC was strengthened by immunohistochemistry (IHC; CD117/c-kit+ and other 14 antigens) and immunofluorescence (IF; CD117/c-kit+ and other 7 antigens). The spatial density of t-ICC (ampullar-segment cryosections) was 100-150 cells/mm2. Non-conventional light microscopy (NCLM) of Epon semithin-sections revealed a network-like distribution of t-ICC in lamina propria and smooth muscle meshwork. t-ICC appeared located beneath of epithelium, in a 10-15 microm thick 'belt', where 18+/-2% of cells were t-ICC. In the whole lamina propria, t-ICC were about 9%, and in muscularis approximately 7%. In toto, t-ICC represent ~8% of subepithelial cells, as counted by NCLM. In vitro, t-ICC were 9.9+/-0.9% of total cell population. TEM showed that the diagnostic 'gold standard' (Huizinga et al., 1997) is fulfilled by 'our' t-ICC. However, we suggest a 'platinum standard', adding a new defining criterion- characteristic cytoplasmic processes (number: 1-5; length: tens of microm; thickness: < or =0.5 microm; aspect: moniliform; branching: dichotomous; organization: network, labyrinthic-system). Quantitatively, the ultrastructural architecture of t-ICC is: nucleus, 23.6+/-3.2% of cell volume, with heterochromatin 49.1+/-3.8%; mitochondria, 4.8+/-1.7%; rough and smooth endoplasmic-reticulum (1.1+/-0.6%, 1.0+/-0.2%, respectively); caveolae, 3.4+/-0.5%. We found more caveolae on the surface of cell processes versus cell body, as confirmed by IF for caveolins. Occasionally, the so-called 'Ca2+-release units' (subplasmalemmal close associations of caveolae+endoplasmic reticulum+mitochondria) were detected in the dilations of cell processes. Electrophysiological single unit recordings of t-ICC in primary cultures indicated sustained spontaneous electrical activity (amplitude of membrane potentials: 57.26+/-6.56 mV). Besides the CD117/c-kit marker, t-ICC expressed variously CD34, caveolins 1&2, alpha-SMA, S-100, vimentin, nestin, desmin, NK-1. t-ICC were negative for: CD68, CD1a, CD62P, NSE, GFAP, chromogranin-A, PGP9.5, but IHC showed the possible existence of (neuro)endocrine cells in tubal interstitium. We call them 'JF cells'. In conclusion, the identification of t-ICC might open the door for understanding some tubal functions, e.g. pace-making/peristaltism, secretion (auto-, juxta- and/or paracrine), regulation of neurotransmission (nitrergic/purinergic) and intercellular signaling, via the very long processes. Furthermore, t-ICC might even be uncommitted bipotential progenitor cells.

Actins↗