Interaction of plasma membrane fibronectin receptor with talin—a transmembrane linkage

Abstract

Many observations suggest the presence of transmembrane linkages between the cytoskeleton and the extracellular matrix. In fibroblasts both light and electron microscopic observations reveal a co-alignment between actin filaments at the cell surface and extracellular fibronectin. These associations are seen at sites of cell matrix interaction, frequently along stress fibres and sometimes where these bundles of microfilaments terminate at adhesion plaques (focal contacts). Non-morphological evidence also indicates a functional linkage between the cytoskeleton and extracellular matrix. Addition of fibronectin to transformed cells induces flattening of the cells and a reorganization of the actin cytoskeleton, with the concomitant appearance of arrays of stress fibres. Conversely, disruption of the actin cytoskeleton by treatment with cytochalasin B leads to release of fibronectin from the cell surface. As yet, there is no detailed knowledge of the molecules involved in this transmembrane linkage, although several proteins have been suggested as candidates in the chain of attachment between bundles of actin filaments and the cytoplasmic face of the plasma membrane: these include vinculin, alpha-actinin and talin, each one having been identified at regions where bundles of actin filaments interact with the plasma membrane and underlying cell-surface fibronectin. Recently, the cell-substrate attachment (CSAT) antigen has been identified as a plasma membrane receptor for fibronectin, raising the possibility that this glycoprotein complex may serve as a bridge between fibronectin and one or more of the underlying cytoskeletal components mentioned. Here we have investigated the interaction of the purified CSAT antigen with these cytoskeletal components, and we demonstrate an interaction specifically between the CSAT antigen and talin.

Adhesion molecule expression in human synovial tissue

“…These molecules make up the VLA proteins (33). p, is widely distributed in human cells and tissues (34) and may be involved in transmembrane signal transduction via interaction with cytoskeletal elements (35). In our study, p,-integrin (CD29) was present to a greater extent on most cell types in noninflammatory tissues.…”

Molecular pathways mediating mechanical signaling in bone

“…For example, both talin and paxillin are unique in that they are known to bind to the focal adhesion targeting sequence of FAK (Schaller, 1996) and talin also binds directly to the integrin cytoplasmic β tail (Horwitz et al, 1986). Paxillin is also a substrate for FAK and src kinase activity and hence a potential signal initiator (Subauste et al, 2004).…”

Scaffold mediated regulation of MAPK signaling and cytoskeletal dynamics: A perspective

“…This is thought to be achieved in part by calpain cleavage of talin, a cytoskeletal anchor that links integrins to actin filaments. Calpain cleavage of talin exposes the N-terminal FERM domain that is then free to bind directly to integrin β subunits [187][188][189] and forge linkages with actin filaments.…”