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.
Fred Hutchinson Cancer Research Center, Seattle, Washington 98109 and the Department of Pathobiology, University of Washington, Seattle, Washington 98195, USA.
B P
BP
Nguyen
S G
SG
Gil
W G
WG
Carter
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