Integrins as receptors for laminins

Abstract

Laminins are a family of trimeric glycoproteins present in the extracellular matrix and the major constituents of basement membranes. Integrins are αβ transmembrane receptors that play critical roles in both cell‐matrix and cell‐cell adhesion. Several members of the integrin family, including α1β1, α2β1, α3β1, α6β1 , α7β1 and α6β4 heterodimers serve as laminin receptors on a variety of cell types. This review summarizes recent advances in understanding the involvement of individual integrins in cell interactions with laminins and the roles of laminin‐binding integrins in adhesion‐mediated events in vertebrates, including embryonic development, cell migration and tumor cell invasiveness, cell proliferation and differentiation, as well as basement membrane assembly. We discuss the regulation of integrin function via alternative splicing of cytoplasmic domains of α and β subunits of the integrin receptors for laminins and present examples of functional collaboration between laminin‐binding integrins and non‐integrin laminin receptors. Advances in our understanding of the laminin‐binding integrins continue to demonstrate the essential roles these receptors play in maintaining cell polarity and tissue architecture. Microsc. Res. Tech. 51:280–301, 2000. © 2000 Wiley‐Liss, Inc.

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“…In our study, rLaminin-521 which was the basement membrane component acted as a scaffold to maintain the cell adhesion [47,48] were used in an attempt to improve cell adhesion factor on the dish in 2D culture. This component was capable of adhering intestinal cells on the dish.…”

Extracellular Matrix Proteins in the Anterior Pituitary Gland

“…The subunits share homology in the cytoplasmic tail, with tyrosine residues able to bind intracellular proteins containing a phosphotyrosine binding domain. The binding of integrins to ECM leads to a conformation change and a signal is activated at the contact site via cytoskeleton proteins such as actin and intermediate filament proteins [20]. The cytoplasmic domain of integrins binds directly or indirectly to several proteins, including talin, vinculin, filamin, paxillin, and tensin [21,22].…”

Incorporation of a laminin-derived peptide (SIKVAV) on polymer-modified adenovirus permits tumor-specific targeting via α6-integrins

“…3,4 The a6-subfamily of integrins are key mediators of cellular interactions with their environment, forming heterodimers with b4 (associated with stable hemidesmosomes and cell-cell adherence) or b1 (involved in the formation of dynamic focal contacts for cell locomotion). In addition, a6 (CD49f) and b1 (CD29) integrins have recently been shown to be stem cell markers being highly expressed on mammary epithelial stem cells.…”

“…Both a6b1 and a6b4 integrins are thought to bind primarily to laminin, specifically the elastasegenerated E8 fragment of the laminin a1 chain. 4 Tashiro et al 23 identified the peptide sequence IKVAV located within the E8 region that promoted cell adhesion, spreading and neurite outgrowth. SIKVAV mediated urokinase-type plasminogen activator (uPa) expression in macrophages 24 and mast cell adherence to a SIKVAV containing peptide 25 can both be blocked using monoclonal antibodies directed against the a6 integrin subunit.…”