PDGF-A interactions with fibronectin reveal a critical role for heparan sulfate in directed cell migration during Xenopus gastrulation.
Platelet-derived growth factor (PDGF) signaling is essential for processes involving cell motility and differentiation during embryonic development in a wide variety of organisms including the mouse, frog, zebrafish, and sea urchin. In early Xenopus laevis embryos, PDGF-AA provides guidance cues for the migration of anterior mesendoderm cells as they move across a fibronectin-rich extracellular matrix. The long form of PDGF-A includes a positively charged carboxyl-terminal retention motif that can interact with the extracellular matrix and heparan sulfate proteoglycans (HSPGs). In this study we demonstrate that PDGF-AA binds directly to fibronectin and that this association is greatly enhanced by heparin. The PDGF-AA-fibronectin binding occurs across a broad range of pHs (5.5-9), which is significant because the PDGF-guided migration of Xenopus mesendoderm cells occurs under basic extracellular conditions (pH 8.4). We further demonstrate that endogenous HSPG''s are required for the PDGF-AA-guided mesendoderm movement, suggesting an in vivo role for HSPGs in mediating the interaction between PDGF-AA and fibronectin.
PubMed ID: 19966216
PMC ID: PMC2799789
Article link: Proc Natl Acad Sci U S A.
Grant support: CA87375 NCI NIH HHS , CA87375 NCI NIH HHS , CA87375 NCI NIH HHS , CA87375 NCI NIH HHS , CA87375 NCI NIH HHS , CA87375 NCI NIH HHS , HL056200 NHLBI NIH HHS , HL056200 NHLBI NIH HHS , HL056200 NHLBI NIH HHS , HL056200 NHLBI NIH HHS , HL056200 NHLBI NIH HHS , HL056200 NHLBI NIH HHS
Genes referenced: fn1 pdgfa