SEARCH · PubMed Health

Results for “Cell Adhesion”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11Linked to original sources

PubMed1988

Cell to cell adhesion systems in Xenopus laevis, the South African clawed toad. II: Monoclonal antibody against a novel Ca2+-dependent cell-cell adhesion glycoprotein on amphibian cells.

We isolated a mouse monoclonal antibody that disrupts Ca2+-dependent cell-cell adhesion of amphibian (Xenopus laevis) cells. When added to culture medium, the monoclonal antibody completely disrupted cell-cell adhesion of amphibian cells in monolayer culture and specifically inhibited Ca2+-dependent cell-cell adhesion of dissociated cells in reaggregation experiments. The monoclonal antibody recognized a 140 kDa cell surface glycoprotein antigenically different from the previously reported Ca2+-dependent cell-cell adhesion molecules (cadherins).

Animals↗

PubMed2005

Shear stress induced release of von Willebrand factor and thrombospondin-1 in HUVEC extracellular matrix enhances breast tumour cell adhesion.

Endothelial cells in vivo are exposed to blood shear forces and flow perturbations induce their activation. Such modifications of hemodynamic can be observed in patients with cancer. We have submitted endothelial cells (HUVEC) to shear stress (13 dynes/cm(2)) and isolated their extracellular matrix (ECM) prior perfusion with breast adenocarcinoma cells (MDA-MB-231) in whole blood at a shear rate of 1500 s(-1). Exposure of HUVEC to 13 dynes/cm(2) (tau(13)) for 2 h enhanced the secretion of von Willebrand factor (vWF) and thrombospondin-1 (TSP-1) in the ECM. Moreover, MDA-MB-231 cell adhesion was enhanced to such treated-ECM. This over-adhesion was inhibited by pre-incubating the ECM with anti-vWF or anti-TSP-1 antibodies, or by blocking tumour cell alpha(v)beta(3) integrin. Although blood platelets were involved in tumour cell adhesion to ECM, blockade of platelet GPIb or alpha(IIb)beta(3) receptors did not specifically inhibit the enhanced tumour cell adhesion observed on tau(13). ECM. These findings indicate that shear stress can modulate the expression of adhesive proteins in ECM, which favours direct tumour cell adhesion via alpha(v)beta(3) and other receptors.

Adenocarcinoma↗

PubMed1991

Artificial cell adhesive proteins engineered by grafting the Arg-Gly-Asp cell recognition signal: factors modulating the cell adhesive activity of the grafted signal.

An artificial cell adhesive protein could be engineered by grafting the RGDS tetrapeptide, the core sequence of the major cell adhesive site of fibronectin, to a truncated form of Staphylococcal protein A (tSPA) via cassette mutagenesis of the tSPA expression vector pRIT2T [T. Maeda et al. (1989) J. Biol. Chem. 264, 15165-15168]. We synthesized a panel of tSPA derivatives grafted with various RGDS-containing oligopeptides to address the problem of how the cell adhesive activity of the resulting tSPA derivatives was affected by the length and amino acid sequence of the grafted oligopeptides and by the sites on tSPA where the extra oligopeptides were inserted. The results showed that (i) the amino acid residues flanking the RGDS core sequence played a key role in modulating the cell adhesive activity of the grafted RGDS signal; (ii) at least two sites on tSPA, each corresponding to on e of the two HindIII sites of pRIT2T, were competent in sustaining the cell adhesive activity of the grafted signal; and (iii) the divalent tSPA containing the RGDS signal at both sites was more active than monovalent derivatives containing only one signal at either site. These results provide a strategic basis for engineering of artificial cell adhesive proteins by grafting the RGDS signal.

Amino Acid Sequence↗

PubMed2001

Evaluation of metallic and polymeric biomaterial surface energy and surface roughness characteristics for directed cell adhesion.

Directed cell adhesion remains an important goal of implant and tissue engineering technology. In this study, surface energy and surface roughness were investigated to ascertain which of these properties show more overall influence on biomaterial-cell adhesion and colonization. Jet impingement was used to quantify cellular adhesion strength. Cellular proliferation and extracellular matrix secretion were used to characterize colonization of 3T3MC fibroblasts on: HS25 (a cobalt based implant alloy, ASTM F75), 316L stainless steel, Ti-6Al4V (a titanium implant alloy), commercially pure tantalum (Ta), polytetrafluoroethylene (PTFE), silicone rubber (SR), and high-density polyethylene (HDPE). The metals exhibited a nearly five-fold greater adhesion strength than the polymeric materials tested. Generally, surface energy was proportional to cellular adhesion strength. Only polymeric materials demonstrated significant increased adhesion strength associated with increased surface roughness. Cellular adhesion on metals demonstrated a linear correlation with surface energy. Less than half as much cellular proliferation was detected on polymeric materials compared to the metals. However the polymers tested demonstrated greater than twice the amount of secreted extracellular matrix (ECM) proteins on a per cell basis than the metallic materials. Thus, surface energy may be a more important determinant of cell adhesion and proliferation, and may be more useful than surface roughness for directing cell adhesion and cell colonization onto engineered tissue scaffoldings.

3T3 Cells↗

PubMed1983

Cell adhesiveness and the cell cycle: correlation in synchronized Balb/c 3T3 cells.

The adhesiveness of Balb/c 3T3 cells partially synchronized either by drug treatment or by the mitotic cell shake-off procedure was assessed by following the aggregation kinetics of aliquots of the cells suspended under defined conditions within the confines of a cone and plate viscometer. M phase cells synchronized by either method were significantly more adherent than appropriate control cells. Cells arrested in S phase following drug treatment were found to be poorly adhesive whereas G1 phase cells prepared by allowing drug treated M phase cells to proceed through mitosis or by treating them with L-histidinol did not differ in their adhesiveness from appropriate control cells. The adhesiveness of control cell populations was found to vary with the extent of re-feeding indicating a possible metabolic dependency of cell adhesion. It is suggested that although M phase cells are poorly adherent to the substrate they are nevertheless considerably adherent in an aggregation system. There was no apparent correlation of the observed increase in intercellular adhesion with any particular stage of M phase (prophase, metaphase, anaphase, telophase). We propose that Balb/c 3T3 cells show an increase in cell-cell adhesiveness as they proceed into M phase and that this is maintained until after division is complete. Our suggestion that certain cell types may interact differently with each other and with the substrate in different stages of the cell cycle could have in vivo relevance in those processes such as tumour spread where considerable cell division is involved.

Animals↗

PubMed1999

Soluble intercellular adhesion molecule, vascular cell adhesion molecule, and impaired microvascular reactivity are early markers of vasculopathy in type 2 diabetic individuals without microalbuminuria.

OBJECTIVE: Using von Willebrand Factor (vWF) as a marker of endothelial function, previous studies have shown that the development of microalbuminuria is associated with the onset of endothelial dysfunction in individuals with type 2 diabetes. We tested the hypothesis that endothelial dysfunction is already evident in normoalbuminuric individuals with type 2 diabetes. RESEARCH DESIGN AND METHODS: We used laser Doppler imaging scanning to measure vasodilation in the forearm skin in response to iontophoresis of 1% acetylcholine (endothelium-dependent) and 1% sodium nitroprusside (endothelium-independent). Multiple indicators of endothelial function--soluble intercellular adhesion molecule (sICAM), soluble vascular cell adhesion molecule (sVCAM), vWF, and microvascular reactivity--were measured in 20 healthy control subjects, 45 normoalbuminuric (urinary albumin/creatinine ratio < 30 micrograms/mg) individuals with type 2 diabetes, and 14 microalbuminuric (urinary albumin/creatinine ratio between 30 and 300 micrograms/mg) individuals with type 2 diabetes. RESULTS: Serum sICAM and sVCAM levels were elevated in the normoalbuminuric (305 +/- 120, 851 +/- 284 ng/ml) and microalbuminuric (300 +/- 89, 845 +/- 252 ng/ml) individuals with diabetes when compared with the healthy control subjects (213 +/- 58, 661 +/- 176 ng/ml) (P < 0.01). Furthermore, the microvascular endothelium-dependent and -independent vasodilation was reduced in the normoalbuminuric (76 +/- 44, 70 +/- 33) (percent increase in perfusion over baseline) and microalbuminuric (74 +/- 41, 73 +/- 28) individuals with diabetes compared with healthy control subjects (126 +/- 67, 120 +/- 47) (P < 0.05). In contrast, plasma vWF was elevated only in the microalbuminuric individuals with diabetes (129 +/- 35%) compared with the normoalbuminuric individuals with diabetes (110 +/- 34) and healthy control subjects (111.3 +/- 39) (P < 0.05). On stepwise multivariate analysis, fasting blood glucose was the most important contributing factor to the variation in microvascular reactivity and sVCAM, whereas insulin resistance (by homeostasis model assessment) was the most important contributing factor to the variation in sICAM. Addition of all clinical and biochemical measures explained only 15-22% of the variation in sICAM, sVCAM, and microvascular reactivity. CONCLUSIONS: Multiple markers of endothelial dysfunction were evident in normoalbuminuric individuals with type 2 diabetes. The pathogenic process of vasculopathy in type 2 diabetes occurs early and may be operative before the development of microalbuminuria.

Adult↗

PubMed2002

Inhibition of tyrosine kinases blocks adhesion-induced T-cell coactivation without interfering with T-cell adhesion to endothelial cell-surface ligands.

Integrin and cell adhesion molecule-regulated cellular adhesion plays an integral part in the recruitment and activation of lymphocytes. T-cell activation is a dynamic process subject to integrin-dependent and -independent regulation. Stimulation of human peripheral blood T cells by the anti-CD3 monoclonal antibody results in a rapid upregulation of integrin affinity. In conjunction with adhesion to endothelial cell-derived ligands and extracellular matrix proteins, anti-CD3 antibodies have been shown to result in significant increases in IL-2 production and T-cell proliferation. Therefore, at least two signal cascades are activated by ligation of the TCR: One results in a change in affinity of integrins for their ligands, whereas the other activates a signaling cascade that leads to gene induction. We investigated the effects of several tyrosine kinase inhibitors on human peripheral blood T-cell adhesion and adhesion-induced costimulation of IL-2 expression and secretion. These compounds did not inhibit anti-CD3-induced short-term (30 min) or long-term (18 hr) T-cell adhesion to VCAM-1, MAdCAM, or ICAM-1. When T cells were stimulated with anti-CD3 and allowed to adhere to VCAM-1, MAdCAM, or ICAM-1 in the presence of these inhibitors; IL-2 production was significantly reduced. The MEK specific inhibitor, PD98059, did not block T-cell adhesion to the various substrates, but it did block IL-2 synthesis. In addition, the tyrosine kinase inhibitors and PD98059 blocked anti-CD3-mediated stimulation of IL-2 synthesis. These data suggest that the signaling mechanism for anti-CD3-mediated integrin activation is distinct from the signaling pathway that results in adhesion-induced IL-2 synthesis via specific integrins and anti-CD3.

Antibodies, Monoclonal↗

PubMedDate not supplied

Development of a novel artificial matrix with cell adhesion peptides for cell culture and artificial and hybrid organs.

The authors present a novel artificial matrix with high cell adhesion and growth rate that was produced by chemical fixation of an RGD-containing peptide (Arg-Gly-Asp) on a polyvinyl alcohol (PVA) surface. The logical sequence behind the molecular design of an artificial matrix that mimics natural adhesive proteins, such as fibronectin, is based on the fact that an RGD tripeptidyl amino sequence is the minimal common adhesion site of adhesive proteins. Activation of surface hydroxyl groups by carbonyl diimidazole successfully incorporated GRGDSP (Gly-Arg-Gly-Asp-Ser-Pro) onto PVA films. The resultant film surface was found to be bioactive, molecularly recognizing the adhesive receptor of bovine endothelial cells. Thus, the artificial matrix mimics active adhesion sites and serves as a novel artificial matrix that may be useful for cell culture, tissue-compatible implants, and hybrid artificial organs.

Animals↗

PubMed1997

Human T-cell lymphotropic virus type 1 (HTLV-1)-induced syncytium formation mediated by vascular cell adhesion molecule-1: evidence for involvement of cell adhesion molecules in HTLV-1 biology.

While studying the potential role of vascular cell adhesion molecule-1 (VCAM-1) in infection of endothelial cells by human immunodeficiency virus (HIV), we found that VCAM-1 can mediate human T-cell lymphotropic virus type 1 (HTLV-1)-induced syncytium formation. Both expression-vector-encoded and endogenously expressed VCAM-1 supported fusion of uninfected cells with HTLV-1-infected cells. Fusion was obtained with cell lines carrying the HTLV-1 genome and expressing viral proteins but not with an HTLV-1-transformed cell line that does not express viral proteins. In clones of VCAM-1-transfected cells, the degree of syncytium formation observed directly reflected the level of VCAM-1 expression. Syncytium formation between HTLV-1-expressing cells and VCAM-1+ cells could be blocked with antiserum against HTLV-1 gp46 and with a monoclonal antibody (MAb) against VCAM-1. Fusion was not blocked by antiserum against HIV or a MAb against VLA-4, the physiological counter-receptor for VCAM-1. The results indicate that VCAM-1 can serve as an accessory molecule or potential coreceptor for HTLV-1-induced cell fusion and provide direct evidence of a role for cell adhesion molecules in the biology of HTLV-1.

Cell Line↗

PubMed1993

[Cell adhesion mediated by ELAM-1 (endothelial leukocyte cell adhesion molecule-1, E-selectin) and carbohydrate determinants].

ELAM-1 (endothelial-leukocyte adhesion molecule-1, E-selectin) is a cell adhesion molecule which is specifically expressed on cytokine-activated endothelial cells. It is known to bind a carbohydrate antigen sialyl Le(x) (sialyl SSEA-1) present on leukocytes, and the sialyl Le(x)/ELAM-1 adhesion system is suggested to play a physiologically important role in leukocyte recruitment in the process of inflammation. Some leukemia cells also express the sialyl Le(x) antigen, and in such a case, the sialyl Le(x)/ELAM-1 adhesion system will be involved in the organ infiltration of leukemia cells. On the other hand, in the adhesion of human cancer cells to endothelial cells, another carbohydrate antigen, sialyl Le(a), serves as the ligand for ELAM-1, as well as sialyl Le(x). These two carbohydrate determinants, sialyl Le(a) and sialyl Le(a), on cancer cells will be involved in the hematogenous metastasis of cancer cells. The physiological function of these two carbohydrate determinants at the surface of normal epithelial cells is most probably to mediate stage-specific cell-to-cell recognition and adhesion during the course of organogenesis in developing embryos, and the abnormal cell-adhesion behaviors of cancer cells are the results of aberrant expression of cell adhesion molecules which would play physiologically important roles under normal condition.

Cell Adhesion↗

PubMed2000

Small GTPases, adhesion, cell cycle control and proliferation.

In many cells, proliferation is under the coordinated control of growth factors and the extracellular matrix (ECM). Autocriny and anchorage-independent growth are observed in many transformed cells where this balance is often altered. The outside-in and inside-out exchanges are mediated by integrins, acting as molecular bridges between the ECM and the cytoskeleton. Integrins, as the major receptors for components of the ECM, are important not only for the physical aspects of cell adhesion, but also for two key aspects of cell fate: cell cycle progression, and apoptosis. The latter aspect will not be covered in the present analysis, which will rather focus on the data accumulated on Ras and Ras-related small GTPases such as Rho, Rac and Cdc42.

Animals↗

PubMed1997

Rat mast cell lines bind to the vascular cell adhesion molecule-1 (VCAM-1) and the mucosal addressin cell adhesion molecule-1 (MAdCAM-1).

Mast cells are key mediators of allergy and inflammation. Increased mast cell numbers are observed in the gut during helminth infestation and at many sites of inflammation. To determine whether mast cells express functional receptors for endothelial cell adhesion molecules, we studied the adhesion of two rat mucosal-type mast cell lines RBL-1 and RCMC-1 to transfected mucosal addressin cell adhesion molecule-1 (MAdCAM-1) and VCAM-1. Both mast cell lines expressed high levels of alpha4 integrins on their surface and bound to CHO cells transfected with VCAM-1. Anti-alpha4 mAbs, TA-2 and L25, inhibited the specific adhesion of the mast cells to VCAM-1 by about 92 and 63%, respectively. Both of the mast cell lines also demonstrated an increased adhesion to CHO cells transfected with MAdCAM-1. The adhesion of RBL-1 to MAdCAM-1 was also significantly inhibited by the anti-alpha4 mAbs TA-2, L25, and HP2/1 by 39, 76, and 42%, respectively. In addition, RBL-1 cells adhered to both VCAM-1 and MAdCAM-1 under both static and nonstatic (shear) conditions, and this was also inhibited by the anti-alpha4 mAb TA-2. Thus, mucosal-type mast cell lines express functional alpha4 integrins that can mediate adhesion to VCAM-1 and MAdCAM-1. These results suggest a mechanism for mast cell accumulation at sites of inflammation and in the gut.

Animals↗

PubMed1992

Adhesion to vascular cell adhesion molecule 1 and fibronectin. Comparison of alpha 4 beta 1 (VLA-4) and alpha 4 beta 7 on the human B cell line JY.

Most mononuclear leukocytes and cell lines express the integrin alpha 4 beta 1 (VLA-4) heterodimer. In this study we have used Northern blotting and immunoprecipitation experiments to demonstrate that a B lymphoblastoid cell line (JY) expressed the integrin beta 7 subunit in association with alpha 4. These alpha 4 beta 7-positive JY cells bound poorly or not at all to VLA-4 ligands (soluble form of vascular cell adhesion molecule 1 (sVCAM-1) and the CS1 region of fibronectin). In contrast, a beta 1-positive variant of JY cells (selected to express a mixture of alpha 4 beta 1 and alpha 4 beta 7) bound avidly to VLA-4 ligands, and this binding was completely inhibitable by anti-alpha 4 and anti-beta 1 monoclonal antibodies. Thus, beta 1 expression appears to be a critically important component of VLA-4-mediated binding to its ligands. After either JY or JY-beta 1 cells were stimulated for 15 min with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate, the majority of adhesion to VCAM or fibronectin remained alpha 4- and beta 1-dependent, but a low amount of adhesion to sVCAM-1 or fibronectin became alpha 4-dependent, beta 1-independent, thus suggesting a role for alpha 4 beta 7. In summary, we have found (i) that alpha 4 beta 7 makes little or no contribution to fibronectin or VCAM-1 binding on unstimulated JY cells, (ii) that alpha 4 beta 7 perhaps makes a minor contribution to ligand binding on 12-O-tetradecanoyl-phorbol-13-acetate-stimulated cells, and (iii) that alpha 4 beta 1 is the functionally dominant VCAM-1 and fibronectin receptor even when expressed in relatively low amounts compared to alpha 4 beta 7.

Antibodies, Monoclonal↗

PubMed1998

Cis-activation of L1-mediated ankyrin recruitment by TAG-1 homophilic cell adhesion.

Neural cell adhesion molecules (CAMs) of the immunoglobulin (Ig) superfamily mediate not only cell aggregation but also growth cone guidance and neurite outgrowth. In this study we demonstrate that two neural CAMs, L1-CAM and TAG-1, induce the homophilic aggregation of Drosophila S2 cells but are unable to interact with each other when expressed on different cells (trans-interaction). However, immunoprecipitations from cells co-expressing L1-CAM and TAG-1 showed a strong cis-interaction between the two molecules in the plane of the plasma membrane. TAG-1 is linked to the membrane by a glycosylphosphatidylinositol (GPI) anchor and therefore is unable to directly interact with cytoplasmic proteins. In contrast, L1-CAM-mediated homophilic cell adhesion induces the selective recruitment of the membrane skeleton protein ankyrin to areas of cell contact. Immunolabeling experiments in which S2 cells expressing TAG-1 were mixed with cells co-expressing L1-CAM and TAG-1 demonstrated that the homophilic interaction between TAG-1 molecules results in the cis-activation of L1-CAM to bind ankyrin. This TAG-1-dependent recruitment of the membrane skeleton provides an example of how GPI-anchored CAMs are able to transduce signals to the cytoplasm. Furthermore, such interactions might ultimately result in the recruitment and the activation of other signaling molecules at sites of cell contacts.

Animals↗

PubMed2006

Maspin is physically associated with [beta]1 integrin regulating cell adhesion in mammary epithelial cells.

Maspin is a tumor-suppressor serpin (serine protease inhibitor), which inhibits cell invasion and migration. Here, we analyzed maspin function in cell adhesion in nontransformed mammary epithelial cells and investigated the underlying mechanism involved in this process. We report that maspin acts in the early steps in the cell adhesion process. Addition of recombinant maspin rapidly increased MCF-10A cell adhesion to the endogenously deposited matrix, and conversely both an antimaspin antibody (Ab) and maspin knockdown by RNA interference resulted in decreased cell adhesion. Mutation analyses revealed that a region of 86 amino acids located between aa 139 and aa 225 was responsible for maspin effect on adhesion. In addition, we show that maspin is associated with detergent-insoluble cortical cytoskeleton elements. Collectively, these results suggest that maspin is part of the supramolecular structure of the adhesion plaque and it modulates cell adhesion via a beta1 integrin-dependent mechanism.

Base Sequence↗

PubMed1998

Rat neutrophils express alpha4 and beta1 integrins and bind to vascular cell adhesion molecule-1 (VCAM-1) and mucosal addressin cell adhesion molecule-1 (MAdCAM-1).

The alpha4 integrins, which are constitutively expressed on all human leukocyte subtypes except neutrophils, interact with vascular cell adhesion molecule-1 (VCAM-1) and mucosal addressin cell adhesion molecule (MAdCAM-1) on endothelium to mediate selective recruitment of leukocyte subpopulations, other than neutrophils, to sites of inflammation. However, here we report that a different paradigm of leukocyte recruitment may exist in the rat. Flow cytometric analysis of rat neutrophils using a panel of monoclonal antibodies which recognize rat alpha4 and beta1 integrins showed consistent, low levels of expression. Although alpha4 was expressed at lower levels on neutrophils than all other rat leukocytes, this level of expression was sufficient to mediate significant levels of alpha4- and beta1-dependent neutrophil adhesion to rat and human VCAM-1, and alpha4-dependent, but beta1-independent, adhesion to human MAdCAM-1. These data suggest that rat neutrophils, unlike other species, may use alpha4 integrins to traffic to sites of inflammation in vivo.

Animals↗

PubMed2006

[Tyrosine kinase inhibitor reverses adriamycin resistance mediated by cell adhesion in RPMI8226 cells].

To study the effects of tyrosine-kinase inhibitor STI571 on the adhesion of RPMI8226 cells to fibronectin (FN), cell adhesion mediated adriamycin-resistance and the Rac1 mRNA expression, the adhesion of RPMI8226 cells to fibronectin and drug resistance mediated by cell adhesion were determined by means of crystal violet staining and MTT assays respectively, Rac1 mRNA levels in RPMI8226 cells were examined by semi-quantitative RT-PCR. The results showed that STI571 could inhibit the adhesion of RPMI8226 cells to fibronectin. When RPMI8226 cells had been adhered to FN or BSA-coated wells for 1, 6 and 12 hours, the adhesion rates were (43.71 +/- 2.18)%, (55.63 +/- 1.56)%, and (63.42 +/- 2.46)% respectively. After treatment with STI571 20 micromol/L, the adhesion rates decreased to (15.12 +/- 1.04)%, (17.58 +/- 1.32)% and (17.24 +/- 1.59)% respectively (P < 0.05). The experiment revealed that growth of RPMI8226 cells adhered to FN-coated plates had a significant advantage over growth on BSA-coated plates when exposed to adriamycin (Adr) for 1 hour followed by a 24-hour culture period, and the mean IC(50) value for FN-adhered cells was (1.46 +/- 0.04) micromol/L while mean IC(50) value for BSA control was (0.78 +/- 0.03) micromol/L (P < 0.05). Following treatment with 20 micromol/L STI571, the mean IC50 values for FN and BSA adhered cells were (0.81 +/- 0.05) micromol/L, (0.74 +/- 0.02) micromol/L respectively, there was no significant difference between them (P > 0.05). RT-PCR demonstrated that the relative Rac1 mRNA level (Rac1/GAPDH) in RPMI8226 cells was downregulated following being treated with 20 micromol/L STI571. It is concluded that STI571 can inhibit the adhesion of RPMI8226 cells to fibronectin, reverse cell adhesion mediated adriamycin-resistance, and downregulate Rac1 mRNA level.

Benzamides↗

PubMed1993

Characterization of cell-adhesive proteins secreted by cell lines growing in protein- and lipid-free synthetic medium: mouse L.P3 cells secrete a procollagen molecule with potent cell-attachment activity.

We have previously shown that mouse L.P3 cells secrete fibronectin and a novel protein, gelatin-non-binding and heparin-binding cell-adhesive protein (GNCP). Here, we screened and characterized cell-adhesive proteins in the conditioned media (CM's) of a series of cell lines growing in a protein- and lipid-free synthetic medium (P3 cell lines). Although cell-attachment activity of the CM's ranged from undetectable to highly significant, fractionation with affinity columns revealed the presence of significant cell-attachment activity in all CM's. Using cell-attachment assay and immunoassay on blotted filters, various cell-adhesive proteins were detected in the CM's, and most of them were identified as fibronectin, laminin, vitronectin, and collagen. GNCP-like proteins were detected in the CM's of HeLa.P3, JTC-16.P3, L.P3, and JTC-12.P3. There was no relationship between the origin of the cell lines and the cell-adhesive proteins secreted. GNCP purified from L.P3-CM was separated into 120-, 140-, 150-, and 160-kDa proteins on SDS-PAGE, which were judged to be a type of mouse type I procollagen from the following results: (1) they were digested by collagenase, (2) pepsin treatment converted the 150- and 160-kDa proteins into 120- and 140-kDa proteins, (3) they were recognized by anti-type I collagen antiserum, and (4) amino-terminal sequence of the pepsin-digested 140-kDa protein had significant homology with type I collagen. GNCP showed half-maximum activity of cell attachment at 0.03 micrograms/ml, indicating that GNCP was a cell-adhesive protein with an extremely high specific activity compared to other known cell-adhesive proteins.

Amino Acid Sequence↗