This superfamily includes the domain found at the N-terminus of KRIT1 (Krev/Rap1 Interaction Trapped-1), mostly characterised in higher eukaryotes. KRIT1 is a 736 amino acid protein that contains three regions, an N-terminal NPxY motif-rich region, an ankyrin repeat domain (ARD) and a band four-point-one, ezrin, radixin, moesin (FERM) domain. The N-terminal region of KRIT1 contains three NPxY-like motifs and can bind ICAP1.

This superfamily entry describes the N-terminal domain, which adopts a Nudix fold, carries three NPxY-like motifs and 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 this domain out-competes the binding of ICAP1 to integrin cytoplasmic tails such that ICAP1 is sequestered in the nucleus. Integrin activation is thus prevented PMID:23317506. KRIT1 does not include the canonical "Nudix box" motif or other Nudix motifs but does, however, very clearly adopt a Nudix fold with a central beta-sheet flanked by two alpha-helices.

INTERPRO:IPR032022 , PFAM:PF16705,DOI:10.1016/j.molcel.2012.12.005