Integrins

Abstract

Integrins are cell adhesion receptors that are evolutionary old and that play important roles during developmental and pathological processes. The integrin family is composed of 24 αβ heterodimeric members that mediate the attachment of cells to the extracellular matrix (ECM) but that also take part in specialized cell-cell interactions. Only a subset of integrins (8 out of 24) recognizes the RGD sequence in the native ligands. In some ECM molecules, such as collagen and certain laminin isoforms, the RGD sequences are exposed upon denaturation or proteolytic cleavage, allowing cells to bind these ligands by using RGD-binding receptors. Proteolytic cleavage of ECM proteins might also generate fragments with novel biological activity such as endostatin, tumstatin, and endorepellin. Nine integrin chains contain an αI domain, including the collagen-binding integrins α1β1, α2β1, α10β1, and α11β1. The collagen-binding integrins recognize the triple-helical GFOGER sequence in the major collagens, but their ability to recognize these sequences in vivo is dependent on the fibrillar status and accessibility of the interactive domains in the fibrillar collagens. The current review summarizes some basic facts about the integrin family including a historical perspective, their structure, and their ligand-binding properties.

Cryo-EM study of slow bee paralysis virus at low pH reveals iflavirus genome release mechanism

“…2H). The RGD sequence enables proteins to bind to integrins (36), which are used as receptors by several viruses (37,38). We previously speculated that SBPV may use integrins to infect honeybee cells (10).…”

Kruppel-like Factor-9 (KLF9) Inhibits Glioblastoma Stemness through Global Transcription Repression and Integrin α6 Inhibition

“…Integrin pathway members, including ITGA6, ITGA9, ARPC1B, CAPN5, GIT1, and MYLK, were found to be particularly enriched for KLF9 down-regulated targets. Integrin signaling modulates various cellular processes, such as proliferation, migration, and differentiation, through cell-cell and cell-matrix interactions (59). Integrins, a family of cell adhesion receptors, are up-regulated in stem cells and are believed to support cell stemness by mediating adhesive interactions between stem cells and their niches (60).…”

Temporal upregulation of host surface receptors provides a window of opportunity for bacterial adhesion and disease

“…Integrins are heterodimeric (composed of two subunits, a and b) transmembrane glycoproteins that attach cells to ECM proteins of the basement membrane or to ligands on other cells [13,14]. Several bacteria bind directly to integrins whereas others engage them via ECM proteins, such as fibronectin and collagen.…”