ICAP-1 is a serine/threonine-rich protein that binds to the cytoplasmic domains of beta-1 integrins in a highly specific manner, binding to a NPXY sequence motif on the beta-1 integrin. The cytoplasmic domains of integrins are essential for cell adhe ...
ICAP-1 is a serine/threonine-rich protein that binds to the cytoplasmic domains of beta-1 integrins in a highly specific manner, binding to a NPXY sequence motif on the beta-1 integrin. The cytoplasmic domains of integrins are essential for cell adhesion, and the fact that phosphorylation of ICAP-1 by interaction with the cell-matrix implies an important role of ICAP-1 during integrin-dependent cell adhesion [1]. Overexpression of ICAP-1 strongly reduces the integrin-mediated cell spreading on extracellular matrix and inhibits both Cdc42 and Rac1. In addition, ICAP-1 induces release of Cdc42 from cellular membranes and prevents the dissociation of GDP from this GTPase [2]. An additional function of ICAP-1 is to promote differentiation of osteoprogenitors by supporting their condensation through modulating the integrin high affinity state [3],
NUDIX, or N-terminal NPxY motif-rich, region of KRIT
NUDIX_5 is found in higher eukaryotes at the N-terminus of KRIT1 or Krev interaction trapped proteins. NUDIX_5 carries three NPxY-like motifs, and it is found to bind the integrin cytoplasmic-associated protein 1 ICAP1. In the absence of KRIT1 ICAP1 ...
NUDIX_5 is found in higher eukaryotes at the N-terminus of KRIT1 or Krev interaction trapped proteins. NUDIX_5 carries three NPxY-like motifs, and it is found to bind the integrin cytoplasmic-associated protein 1 ICAP1. In the absence of KRIT1 ICAP1 binds via its C-terminal PH/PTB fold domain to the integrin beta-1 cytoplasmic tail. Binding of KRIT1 to ICAP1 via NUDIX_5 out-competes the binding of ICAP1 to integrin cytoplasmic tails such that ICAP1 is sequestered in the nucleus. Integrin activation is thus prevented [1].
