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Avril V Somlyo

Publications and source records attributed to Avril V Somlyo.

At least 19 recordsLinked to original sources
PubMed2006

Assessment of contractility of purified smooth muscle cells derived from embryonic stem cells.

The aims of this study were to develop a method for deriving purified populations of contractile smooth muscle cells (SMCs) from embryonic stem cells (ESCs) and to characterize their function. Transgenic ESC lines were generated that stably expressed a puromycin-resistance gene under the control of either a smooth muscle alpha-actin (SMalphaAlpha) or smooth muscle-myosin heavy chain (SM-MHC) promoter. Negative selection, either overnight or for 3 days, was then used to purify SMCs from embryoid bodies. Purified SMCs expressed multiple SMC markers by immunofluorescence, immunoblotting, quantitative reverse transcription-polymerase chain reaction, and flow cytometry and were designated APSCs (SMalphaAlpha-puromycin-selected cells) or MPSCs (SM-MHC-puromycin-selected cells), respectively. Both SMC lines displayed agonist-induced Ca(2+) transients, expressed functional Ca(2+) channels, and generated contractile force when aggregated within collagen gels and stimulated with vasoactive agonists, such as endothelin-1, or in response to depolarization with KCl. Importantly, subcutaneous injection of APSCs or MPSCs subjected to 18 hours of puromycin selection led to the formation of teratomas, presumably due to residual contamination by pluripotent stem cells. In contrast, APSCs or MPSCs subjected to prolonged puromycin selection for 3 days did not form teratomas in vivo. These studies describe for the first time a method for generating relatively pure populations of SMCs from ESCs which display appropriate excitation and contractile responses to vasoactive agonists. However, studies also indicate the potential for teratoma development in ESC-derived cell lines, even after prolonged differentiation, highlighting the critical requirement for efficient methods of separating differentiated cells from residual pluripotent precursors in future studies that use ESC derivatives, whether SMC or other cell types, in tissue engineering applications.

Actins↗
PubMed2005

Telokin mediates Ca2+-desensitization through activation of myosin phosphatase in phasic and tonic smooth muscle.

Telokin, a 17 kDa smooth muscle specific protein, consists of the C-terminal domain of MLCK, is phosphorylated by PKA and PKG at Ser13 in vivo (Wu et al. (1998) J Biol Chem 273: 11362-11369; Walker et al. (2001) J. Biol Chem 276: 24519-24524) and is proposed to induce Ca2+-desensitization through activation of myosin phosphatase (Wu et al. (1998) J. Biol Chem 273: 11362-11369). Telokin is reported to be highly expressed in phasic with only trace amounts in tonic smooth muscle. In alpha-toxin permeabilized femoral artery, 5 microM 8-Br-cGMP induced a two-fold increase in telokin phosphorylation and a maximal 30% relaxation of Ca2+-activated force compared to a 90% relaxation in phasic ileum muscle consistent with the relative amounts of telokin expressed in ileum, 27+/-4.6 microM SEM compared to 6+/-1.7 microM SEM, in femoral artery. Recombinant Wt telokin and the phospho-telokin mutant, S13D relaxed telokin-depleted femoral artery, by 38+/-8% SEM and 60+/-20% SEM, respectively. 8-Br-cGMP increased the rate and decreased the amplitude of force development initiated by photolysis of caged ATP in alpha-toxin permeabilized ileum and femoral artery smooth muscle, consistent with a cGMP-induced increase in phosphatase activity. Similarly, in telokin depleted ileum, recombinant S13D mutant telokin significantly increased the rate (0.08+/-0.01 s-1 vs. 014+/-0.02 s-1) and decreased force amplitude. In conclusion, our data support a role for telokin in cyclic nucleotide-induced relaxation of not only phasic, but also tonic smooth muscle and that this relaxation is mediated by activation of myosin phosphatase activity leading to a decrease in myosin light chain phosphorylation.

Adenosine Triphosphate↗
PubMed2004

Smooth muscle myosin: regulation and properties.

The relationship of the biochemical states to the mechanical events in contraction of smooth muscle cross-bridges is reviewed. These studies use direct measurements of the kinetics of Pi and ADP release. The rate of release of Pi from thiophosphorylated cycling cross-bridges held isometric was biphasic with turnovers of 1.8 s-1 and 0.3 s-1, reflecting properties and forces directly acting on cross-bridges through mechanisms such as positive strain and inhibition by high-affinity MgADP binding. Fluorescent transients reporting release of an ADP analogue 3'-deac-edaADP were significantly faster in phasic than in tonic smooth muscles. Thiophosphorylation of myosin regulatory light chains (RLCs) increased and positive strain decreased the release rate around twofold. The rates of ADP release from rigor cross-bridges and the steady-state Pi release from cycling isometric cross-bridges are similar, indicating that the ADP-release step or an isomerization preceding it may limit the ATPase rate. Thus ADP release in phasic and tonic smooth muscles is a regulated step with strain- and dephosphorylation-dependence. High affinity of cross-bridges for ADP and slow ADP release prolong the fraction of the duty cycle occupied by strongly bound AM.ADP state(s) and contribute to the high economy of force that is characteristic of smooth muscle. RLC thiophosphorylation led to structural changes in smooth muscle cross-bridges consistent with our findings that thiophosphorylation and strain modulate product release.

Actins↗
PubMed2004

Uncoupling of GPCR and RhoA-induced Ca2+-sensitization of chicken amnion smooth muscle lacking CPI-17.

Ca2+-sensitization of smooth muscle occurs through inhibition of myosin light chain phosphatase (MLCP) leading to an increase in the MLCK:MLCP activity ratio. MLCP is inhibited through phosphorylation of its regulatory subunit (MYPT-1) following activation of the RhoA/Rho kinase (ROK) pathway or through phosphorylation of the PP1c inhibitory protein, CPI-17, by PKC delta or ROK. Here, we explore the crosstalk between these two modes of MLCP inhibition in a smooth muscle of a natural CPI-17 knockout, chicken amnion. GTPgammaS elicited Ca2+-sensitized force which was relaxed by GDI or Y-27632, however, U46619, carbachol and phorbol ester failed to induce Ca2+-sensitized force, but were rescued by recombinant CPI-17, and were sensitive to Y-27632 inhibition. In the presence, but not absence, of CPI-17, U46619 also significantly increased GTP.RhoA. There was no affect on MYPT-1 phosphorylation at T695, however, T850 phosphorylation increased in response to GTPgammaS stimulation. Together, these data suggest a role for CPI-17 upstream of RhoA activation possibly through activation of another PP1 family member targeted by CPI-17.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed2004

ANG II type 2 receptor regulates smooth muscle growth and force generation in late fetal mouse development.

Although evidence from culture studies implicates the angiotensin II (ANG II) type 2 receptor (AT(2)R) in the regulation of growth and differentiation of arterial smooth muscle (SM) cells (SMC), the lack of its expression in adult arteries has precluded direct investigation of its role in vivo. The goal of the present study was to determine the role of AT(2)R in the control of fetal SMC growth, contractility, and differentiation during vascular development. Determination of isometric tension in fetal aortas showed potentiated ANG II-induced contraction by treatment with the selective AT(2)R antagonist PD-123319, demonstrating the presence of functional AT(2)Rs that mediate reduced force development in vascular SMC. In direct contrast to numerous cell culture studies, proliferation indexes were decreased rather than increased in aortic SMC of fetal homozygous AT(2)R knockout compared with wild-type or heterozygous knockout mice. Experiments using SMC tissues from heterozygous female AT(2)R knockout mice, which are naturally occurring chimeras for AT(2)R expression, showed that AT(2)R mRNA expression was exactly 50% of that of wild type. This indicated that loss of AT(2)R expression did not confer a selective advantage or disadvantage for SMC lineage determination and expansion. Real time RT-PCR analyses showed no significant difference in expression of SM-alpha-actin, SM myosin heavy chain, and myocardin in various SM tissues from all three genotypes, suggesting that knockout of AT(2)R had no effect on subsequent SMC differentiation. Taken together, results indicate that functional AT(2)R are expressed in fetal aorta and mediate reduced force development but do not significantly contribute to regulation of SMC differentiation.

Actins↗
PubMed2004

The crystal structure of RhoA in complex with the DH/PH fragment of PDZRhoGEF, an activator of the Ca(2+) sensitization pathway in smooth muscle.

Calcium sensitization in smooth muscle is mediated by the RhoA GTPase, activated by hitherto unspecified nucleotide exchange factors (GEFs) acting downstream of Galphaq/Galpha(12/13) trimeric G proteins. Here, we show that at least one potential GEF, the PDZRhoGEF, is present in smooth muscle, and its isolated DH/PH fragment induces calcium sensitization in the absence of agonist-mediated signaling. In vitro, the fragment shows high selectivity for the RhoA GTPase. Full-length fragment is required for the nucleotide exchange, as the isolated DH domain enhances it only marginally. We crystallized the DH/PH fragment of PDZRhoGEF in complex with nonprenylated human RhoA and determined the structure at 2.5 A resolution. The refined molecular model reveals that the mutual disposition of the DH and PH domains is significantly different from other previously described complexes involving DH/PH tandems, and that the PH domain interacts with RhoA in a unique mode. The DH domain makes several specific interactions with RhoA residues not conserved among other Rho family members, suggesting the molecular basis for the observed specificity.

Blotting, Western↗
PubMed2004

Myosin regulatory light chain phosphorylation and strain modulate adenosine diphosphate release from smooth muscle Myosin.

The effects of myosin regulatory light chain (RLC) phosphorylation and strain on adenosine diphosphate (ADP) release from cross-bridges in phasic (rabbit bladder (Rbl)) and tonic (femoral artery (Rfa)) smooth muscle were determined by monitoring fluorescence transients of the novel ADP analog, 3'-deac-eda-ADP (deac-edaADP). Fluorescence transients reporting release of 3'-deac-eda-ADP were significantly faster in phasic (0.57 +/- 0.06 s(-1)) than tonic (0.29 +/- 0.03 s(-1)) smooth muscles. Thiophosphorylation of regulatory light chains increased and strain decreased the release rate approximately twofold. The calculated (k-ADP/k+ADP) dissociation constant, Kd of unstrained, unphosphorylated cross-bridges for ADP was 0.6 microM for rabbit bladder and 0.3 microM for femoral artery. The rates of ADP release from rigor bridges and reported values of Pi release (corresponding to the steady-state adenosine triphosphatase (ATPase) rate of actomyosin (AM)) from cross-bridges during a maintained isometric contraction are similar, indicating that the ADP-release step or an isomerization preceding it may be limiting the adenosine triphosphatase rate. We conclude that the strain- and dephosphorylation-dependent high affinity for and slow ADP release from smooth muscle myosin prolongs the fraction of the duty cycle occupied by strongly bound actomyosin.ADP state(s) and contributes to the high economy of force.

Actomyosin↗
PubMed2003

Modulation of Ca2+ sensitivity by cyclic nucleotides in smooth muscle from protein kinase G-deficient mice.

The cGMP-dependent protein kinase (PKG) is the main mediator of nitric oxide-induced relaxation of smooth muscle. Although this pathway is well established, the cellular action of PKG, nitric oxide, and cGMP is complex and not fully understood. A cross-talk between the cGMP-PKG and other pathways (e.g. cAMP-protein kinase A) seems to exist. We have explored cGMP- and cAMP-dependent relaxation of smooth muscle using PKG-deficient mice (cGKI-/-). In intact ileum strips of wild type mice (cGKI+/+), 8-Br-cGMP inhibited the sustained phase of carbachol contractions by approximately 80%. The initial peak was less inhibited (approximately 30%). This relaxation was associated with a reduction in intracellular [Ca2+] and decreased Ca2+ sensitivity. Contractions of cGKI-/- ileum were not influenced by 8-Br-cGMP. EC50 for 8-Br-cGMP for PKG was estimated to be 10 nm. PKG-independent relaxation by 8-Br-cGMP had an EC50 of 10 microm. Relaxation by cAMP (approximately 50% at 100 microm), Ca2+ sensitivity of force, and force potentiation by GTPgammaS were similar in cGKI+/+ and cGKI-/- tissues. The results show that PKG is the main target for cGMP-induced relaxation in intestinal smooth muscle. cGMP desensitize the contractile system to Ca2+ via PKG. PKG-independent pathways are activated at 1000-fold higher cGMP concentrations. Relaxation by cAMP can occur independently of PKG. Long term deficiency of PKG does not lead to an apparent up-regulation of the cAMP-dependent pathways or changes in Ca2+ sensitivity.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed2003

Cryo-atomic force microscopy of unphosphorylated and thiophosphorylated single smooth muscle myosin molecules.

The purpose of this study was to determine whether steric blockage of one head by the second head of native two-headed myosin was responsible for the inactivity of nonphosphorylated two-headed myosin compared with the high activity of single-headed myosin, as suggested on the basis of electron microscopy of two-dimensional crystals of heavy meromyosin (Wendt, T., Taylor, D., Messier, T., Trybus, K. M., and Taylor, K. A. (1999) J. Cell Biol. 147, 1385-1390; and Wendt, T., Taylor, D., Trybus, K. M., and Taylor, K. (2001) Proc. Natl. Acad. Sci. U. S. A. 98, 4361-4366). Our earlier cryo-atomic force microscopy (cryo-AFM) (Zhang, Y., Shao, Z., Somlyo, A. P., and Somlyo, A. V. (1997) Biophys. J. 72, 1308-1318) indicates that thiophosphorylation of the regulatory light chain increases the separation of the two heads of a single myosin molecule, but the thermodynamic probability of steric hindrance by strong binding between the two heads was not determined. We now report this probability determined by cryo-AFM of single whole myosin molecules shown to have normal low ATPase activity (0.007 s-1). We found that the thermodynamic probability of the relative head positions of nonphosphorylated myosin was approximately equal between separated heads as compared with closely apposed heads (energy difference of 0.24 kT (where k is a Boltzman constant and T is the absolute temperature)), and thiophosphorylation increased the number of molecules having separated heads (energy advantage of -1.2 kT (where k is a Boltzman constant and I is the absolute temperature)). Our results do not support the suggestion that strong binding of one head to the other stabilizes the blocked conformation against thermal fluctuations resulting in steric blockage that can account for the low activity of nonphosphorylated two-headed myosin.

Animals↗
PubMed2003

LPP, a LIM protein highly expressed in smooth muscle.

An 80-kDa protein, prominently expressed in smooth muscle, was microsequenced and identified as LPP, the product of the lipoma-preferred partner gene (Petit MMR, Mols R, Schoenmakers EFPM, Mandahl N, and Van de Ven WJM. Genomics 36: 118-129, 1996). Using a specific anti-LPP antibody, we showed, in Western blots and with immunofluorescence microscopy, the selective expression of LPP in vascular and visceral smooth muscles (approximately 0.5-1 ng/microg total protein). In other mature (noncultured) tissues, including heart and skeletal muscle, the protein is present only in trace amounts and is closely correlated with the levels of the smooth muscle marker alpha-actin. In freshly isolated guinea pig bladder smooth muscle cells, immunofluorescence images showed LPP as linear arrays of punctate, longitudinally oriented staining superimposed with vinculin staining on the plasma membrane surface. A corresponding pattern of periodic labeling at the membrane in transverse sections of bladder smooth muscle suggested an association of LPP with peripheral dense bodies. In cultured rat aortic smooth muscle cells, LPP colocalized with vinculin at focal adhesions but not with p120 catenin or alpha-actinin. Overexpression of the protein increased EGF-stimulated migration of vascular smooth muscle cells in Transwell assays, suggesting the participation of LPP in cell motility. The Rho-kinase inhibitor Y-27632 dissociated focal adhesions and LPP staining at the cell periphery and enhanced the nuclear accumulation of LPP induced by leptomycin B, indicating that LPP has a potential for relocating to the nucleus through a shuttling mechanism that is sensitive to inhibition of Rho-kinase.

Active Transport, Cell Nucleus↗
PubMed2003

Intracellular chloride accumulation and subcellular elemental distribution during atrial fibrillation.

BACKGROUND: Ion channel remodeling occurs during atrial fibrillation (AF); however, the extent of alteration in the subcellular distribution of elements (Na, K, Cl, Ca, Mg, P) is unknown. Electron probe microanalysis was used to determine the total (free+bound) in vivo subcellular concentration of these elements during AF. METHODS AND RESULTS: The left atrial appendage (LAA) was snap-frozen in situ after pacing (640 bpm) for 3 minutes (n=5 dogs), 30 minutes (n=3), or 48 hours (n=5). Dogs in sinus rhythm (n=3) served as controls. Whole-cell, cytosolic, and mitochondrial elemental concentrations were measured in cryosections. LAA effective refractory period (ERP) was measured before and after pacing. LAA ERP decreased significantly after 48 hours (116+/-3 to 88+/-10 ms, P=0.02). Whole-cell Cl increased by 9.0 mmol/L and 17 mmol/L after 3 and 30 minutes of pacing, respectively (P<0.0001), without a concomitant increase in Na. However, at 48 hours, whole-cell Na was reduced by 51% (P<0.01). Cytosolic Ca increased by 1.1 mmol/kg dry wt after 3 minutes (P<0.005), but mitochondrial Ca remained low and unchanged. Cell size measured in transverse cryosections increased after 3 minutes of pacing (75+/-5 to 109+/-11 microm2, P=0.007) but returned to baseline by 30 minutes (66+/-5 microm2). CONCLUSIONS: Intracellular Cl accumulation induced by rapid pacing is a novel finding and may play a role in AF pathogenesis by causing resting membrane depolarization and ERP reduction. There was no evidence of cellular or mitochondrial Ca overload despite the development of electrical remodeling and transient increase in cytoplasmic Ca.

Animals↗
PubMed2003

Calcium content of peripheral and central mitochondria in the guinea pig myocardium: electron probe analysis.

We quantitated subcellular elemental concentrations in stimulated and resting guinea pig myocardium to determine whether species-specific properties of guinea pigs or the subcellular localization of mitochondria accounted for reports of higher mitochondrial Ca in guinea pigs than in other species. Small papillary muscles or trabeculae isolated from guinea pig ventricles were stimulated to raise cytosolic [Ca(2+)](i) by two methods: (1). tetanizing by rapid pacing preparations in which Ca(2+) uptake by the sarcoplasmic reticulum was inhibited with cyclopiazonic acid or (2). freeze trapping paced muscles near-peak systole. Electron probe X-ray microanalysis showed no significant difference between the (low, approximately 0.4 mmol/kg dry weight) mitochondrial Ca content of stimulated guinea pig hearts, compared to mitochondria of other species, such as rat and hamsters, and the Ca contents of peripheral and central mitochondria were also not significantly different.

Animals↗
PubMed2003

Rho kinase and matrix metalloproteinase inhibitors cooperate to inhibit angiogenesis and growth of human prostate cancer xenotransplants.

The purpose of this study was to determine the effects of inhibitors of Rho kinase (ROK) and matrix metalloproteinases (MMPs) on angiogenesis and tumor growth and to evaluate ROK activity in human prostate cancer PC3 cells and endothelial cells (HUVECs). Vacuolation by endothelial cells and lumen formation, the earliest detectable stages of angiogenesis, were inhibited by the ROK inhibitor Wf-536. Combining Wf-536 with the MMP inhibitor Marimastat greatly enhanced in vitro inhibition of endothelial vacuolation, lumen and cord formation, and VEGF- and HGF-stimulated endothelial sprout formation from aorta. Inhibition of sprout formation by the two inhibitors was synergistic. Both agents inhibited migration of HUVECs. The regulatory subunit (MYPT1) of the myosin phosphatase was phosphorylated in PC3 cells and HUVECs, and phosphorylation of MYPT1 and the myosin regulatory light chain was reduced by Wf-536, providing direct evidence of ROK activity. Early treatment of immuno-incompetent mice bearing xenotransplants of PC3 cells with a combination of Wf-536 plus Marimastat with or without Paclitaxel, significantly inhibited tumor growth, prevented tumor growth escape after discontinuation of Paclitaxel, and increased survival.

Amides↗
PubMed2003

Ca2+ sensitivity of smooth muscle and nonmuscle myosin II: modulated by G proteins, kinases, and myosin phosphatase.

Ca2+ sensitivity of smooth muscle and nonmuscle myosin II reflects the ratio of activities of myosin light-chain kinase (MLCK) to myosin light-chain phosphatase (MLCP) and is a major, regulated determinant of numerous cellular processes. We conclude that the majority of phenotypes attributed to the monomeric G protein RhoA and mediated by its effector, Rho-kinase (ROK), reflect Ca2+ sensitization: inhibition of myosin II dephosphorylation in the presence of basal (Ca2+ dependent or independent) or increased MLCK activity. We outline the pathway from receptors through trimeric G proteins (Galphaq, Galpha12, Galpha13) to activation, by guanine nucleotide exchange factors (GEFs), from GDP. RhoA. GDI to GTP. RhoA and hence to ROK through a mechanism involving association of GEF, RhoA, and ROK in multimolecular complexes at the lipid cell membrane. Specific domains of GEFs interact with trimeric G proteins, and some GEFs are activated by Tyr kinases whose inhibition can inhibit Rho signaling. Inhibition of MLCP, directly by ROK or by phosphorylation of the phosphatase inhibitor CPI-17, increases phosphorylation of the myosin II regulatory light chain and thus the activity of smooth muscle and nonmuscle actomyosin ATPase and motility. We summarize relevant effects of p21-activated kinase, LIM-kinase, and focal adhesion kinase. Mechanisms of Ca2+ desensitization are outlined with emphasis on the antagonism between cGMP-activated kinase and the RhoA/ROK pathway. We suggest that the RhoA/ROK pathway is constitutively active in a number of organs under physiological conditions; its aberrations play major roles in several disease states, particularly impacting on Ca2+ sensitization of smooth muscle in hypertension and possibly asthma and on cancer neoangiogenesis and cancer progression. It is a potentially important therapeutic target and a subject for translational research.

Animals↗
PubMed2002

RhoA-mediated Ca2+ sensitization in erectile function.

A Rho-kinase inhibitor increases corpus cavernosum (CC) pressure in an in vivo rat model (Chitaley, K., Wingard, C. J., Webb, R. C., Branam, H., Stopper, V. S., Lewis, R. W., and Mills, T. M. (2001) Nat. Med. 7, 119-122) suggesting that Rho-mediated Ca(2+) sensitization of CC smooth muscle maintains the flaccid (contracted) state. We directly demonstrate Ca(2+) sensitization of permeabilized rabbit and human CC and identify a highly expressed molecular component of this pathway. Ca(2+) sensitization of force induced by endothelin or GTPgammaS was significantly greater in CC than in rabbit ileum smooth muscle and was accompanied by a 17-fold higher RhoA content. Pull-down assays with the RhoA binding domain of mDia showed the high RhoA content of CC to be available for activation by GTPgammaS. Ca(2+) sensitization induced by endothelin, phenylephrine, or GTPgammaS was completely relaxed by the Rho kinase inhibitor Y-27632. Human and rabbit CC both express the phosphatase inhibitor CPI-17, the myosin phosphatase regulatory (MYPT-1) and catalytic (PP1delta) subunits, and two isoforms of Rho kinase. We suggest that high expression of RhoA contributes, through RhoA-mediated Ca(2+) sensitization, to the flaccid state of CC that can be reversed by a water-soluble, orally active Rho kinase inhibitor suitable for therapy of erectile dysfunction.

Animals↗
PubMed2002

Cooperativity between the Ras-ERK and Rho-Rho kinase pathways in urokinase-type plasminogen activator-stimulated cell migration.

Binding of the urokinase-type plasminogen activator (uPA) to its receptor activates diverse cell signaling pathways. How these signals are integrated so that cell physiology is altered remains unclear. In this study, we demonstrated that migration of MCF-7 breast cancer cells and HT-1080 fibrosarcoma cells on serum-coated surfaces is stimulated by agents that activate ERK, including uPA, epidermal growth factor, and constitutively active MEK1. The promigratory activity of these agents was entirely blocked not only by the MEK-specific antagonist PD098059, but also by antagonists of the Rho-Rho kinase pathway, including Y-27632 and dominant-negative RhoA (RhoA-N19). uPA did not significantly increase the level of GTP-bound RhoA, suggesting that the constitutive activity of the Rho-Rho kinase pathway may be sufficient to support ERK-stimulated cell migration. Paradoxically, Y-27632 and RhoA-N19 increased ERK phosphorylation in MCF-7 cells, providing further evidence that ERK activation alone does not promote cell migration when Rho kinase is antagonized. When MCF-7 cell migration was stimulated by ERK-independent processes such as expression of the beta(3) integrin subunit or changing the substratum to type I collagen, Y-27632 and RhoA-N19 failed to inhibit the response. This study supports a model in which the Ras-ERK and Rho-Rho kinase pathways cooperate to promote cell migration. Neutralizing either pathway is sufficient to block the response to agents that stimulate cell migration by activating ERK.

Amides↗