title: Inhibitory role of alpha 6 beta 4-associated erbB-2 and phosphoinositide 3-kinase in keratinocyte haptotactic migration dependent on alpha 3 beta 1 integrin.
abstract: Keratinocytes and other epithelial cells express two receptors for the basement membrane (BM) extracellular matrix component laminin-5 (Ln-5), integrins alpha 3 beta 1 and alpha 6 beta 4. While alpha 3 beta 1 mediates adhesion, spreading, and migration (Kreidberg, J.A. 2000. Curr. Opin. Cell Biol. 12:548--553), alpha 6 beta 4 is involved in BM anchorage via hemidesmosomes (Borradori, L., and A. Sonnenberg. 1999. J. Invest. Dermatol. 112:411--418). We investigated a possible regulatory interplay between alpha 3 beta 1 and alpha 6 beta 4 in cell motility using HaCaT keratinocytes as a model. We found that alpha 6 beta 4 antibodies inhibit alpha 3 beta 1-mediated migration on Ln-5, but only when migration is haptotactic (i.e., spontaneous or stimulated by alpha 3 beta 1 activation), and not when chemotactic (i.e., triggered by epidermal growth factor receptor). Inhibition of migration by alpha 6 beta 4 depends upon phosphoinositide 3-kinase (PI3-K) since it is abolished by PI3-K blockers and by dominant-negative PI3-K, and constitutively active PI3-K prevents haptotaxis. In HaCaT cells incubated with anti-alpha 6 beta 4 antibodies, activation of PI3-K is mediated by alpha 6 beta 4-associated erbB-2, as indicated by erbB-2 autophosphorylation and erbB-2/p85 PI3-K coprecipitation. Furthermore, dominant-negative erbB-2 abolishes inhibition of haptotaxis by anti-alpha 6 beta 4 antibodies. These results support a model whereby (a) haptotactic cell migration on Ln-5 is regulated by concerted action of alpha 3beta 1 and alpha 6 beta 4 integrins, (b) alpha 6 beta 4-associated erbB-2 and PI3-K negatively affect haptotaxis, and (c) chemotaxis on Ln-5 is not affected by alpha 6 beta 4 antibodies and may require PI3-K activity. This model could be of general relevance to motility of epithelial cells in contact with BM.
authors.affiliation: Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
authors.forename: Edith
authors.initials: E
authors.lastname: Hintermann
authors.forename: Martin
authors.initials: M
authors.lastname: Bilban
authors.forename: Andrew
authors.initials: A
authors.lastname: Sharabi
authors.forename: Vito
authors.initials: V
authors.lastname: Quaranta
mesh_terms: D000954:Antigens, Surface / Q000378:metabolism*; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology*; D002633:Chemotaxis / Q000502:physiology; D006801:Humans; D039201:Integrin alpha3beta1; D039161:Integrin alpha6beta4; D016023:Integrins / Q000378:metabolism*; D015603:Keratinocytes / Q000502:physiology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D017474:Receptors, Laminin; D015398:Signal Transduction; D000097794:Kalinin
chemical_list: D000954:Antigens, Surface; D015815:Cell Adhesion Molecules; D039201:Integrin alpha3beta1; D039161:Integrin alpha6beta4; D016023:Integrins; D019869:Phosphatidylinositol 3-Kinases; D018719:Erb-b2 Receptor Tyrosine Kinases; D017474:Receptors, Laminin; D000097794:Kalinin