Deposition of laminin 5 by keratinocytes regulates integrin adhesion and signaling.
Deposition of laminin 5 over exposed dermal collagen in epidermal wounds is an early event in repair of the basement membrane. We report that deposition of laminin 5 onto collagen switches adhesion and signaling from collagen-dependent to laminin 5-dependent. Ligation of laminin 5 by integrin alpha(6)beta(4) activates phosphoinositide 3-OH-kinase (PI3K) signaling. This activation allows for adhesion and spreading via integrin alpha(3)beta(1) on laminin 5 independent of RhoGTPase, a regulator of actin stress fibers. In contrast, adhesion and spreading on collagen via alpha(2)beta(1) is Rho-dependent and is inhibited by toxin B, a Rho inhibitor. Deposition of laminin 5 and ligation of alpha(6)beta(4) increases PI3K-dependent production of phosphoinositide di- and triphosphates, PI3K activity, and phosphorylation of downstream target protein c-Jun NH(2)-terminal kinase. Conversely, blocking laminin 5-deposition with brefeldin A, an inhibitor of vesicle transport, or with anti-laminin 5 monoclonal antibodies abolishes the PI3K-dependent spreading mediated by alpha(3)beta(1) and phosphorylation of c-Jun NH(2)-terminal kinase. Studies with keratinocytes lacking alpha(6)beta(4) or laminin 5 confirm that deposition of laminin 5 and ligation by alpha(6)beta(4) are required for PI3K-dependent spreading via alpha(3)beta(1). We suggest that deposition of laminin 5 onto the collagen substratum, as in wound repair, enables human foreskin keratinocytes to interact via alpha(6)beta(4) and to switch from a RhoGTPase-dependent adhesion on collagen to a PI3K-dependent adhesion and spreading mediated by integrin alpha(3)beta(1) on laminin 5.
Nguyen
B P
BP
Fred Hutchinson Cancer Research Center, Seattle, Washington 98109 and the Department of Pathobiology, University of Washington, Seattle, Washington 98195, USA.
Gil
S G
SG
Carter
W G
WG
D000595:Amino Acid Sequence; D000730:Androstadienes / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D015815:Cell Adhesion Molecules / Q000737:chemistry / Q000378:metabolism*; D002465:Cell Movement / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism; D004820:Epidermolysis Bullosa / Q000378:metabolism; D005083:Exfoliatins / Q000494:pharmacology; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D022001:Focal Adhesions / Q000187:drug effects; D006493:Heparin / Q000378:metabolism; D006801:Humans; D016023:Integrins / Q000378:metabolism*; D048031:JNK Mitogen-Activated Protein Kinases; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D000077191:Wortmannin; D014945:Wound Healing; D020741:rho GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D000097794:Kalinin
D000730:Androstadienes; D015815:Cell Adhesion Molecules; D003094:Collagen; D005083:Exfoliatins; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D006493:Heparin; D016023:Integrins; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D010716:Phosphatidylinositols; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011505:Protein-Tyrosine Kinases; D000077191:Wortmannin; D020741:rho GTP-Binding Proteins; D000097794:Kalinin; C496050:PTK2 protein, human