A PTP-PEST-like protein affects α5β1-integrin-dependent matrix assembly, cell adhesion, and migration in Xenopus gastrula

AbstractDuring amphibian gastrulation, mesodermal cell movements depend on both cell–cell and cell–matrix interactions. Ectodermal cells from the blastocoel roof use α5β1 integrins to assemble a fibronectin-rich extracellular matrix on which mesodermal cells migrate using the same α5β1 integrin. In this report, we show that the tyrosine phosphatase xPTP-PESTr can prevent fibronectin fibril formation when overexpressed in ectodermal cells resulting in delayed gastrulation. In addition, isolated ectodermal cells overexpressing xPTP-PESTr are able to spread on fibronectin using the α5β1 integrin in the absence of activin-A induction and before the onset of gastrulation. We further show that while the inhibition of fibrillogenesis depends on the phosphatase activity of xPTP-PESTr, induction of cell spreading does not. Finally, while cell spreading is usually associated with cell migration, xPTP-PESTr promotes ectodermal cell spreading on fibronectin but also reduces cell migration in response to activin-A, suggesting an adverse effect on cell translocation. We propose that xPTP-PESTr overexpression adversely affect cell migration by preventing de-adhesion of cells from the substrate