This domain is found in E3 ubiquitin-protein ligase TTC3 and DZIP3, its function is unknown.TTC3 mediates ubiquitination and degradation of phosphorylated Akt, which seems to be its preferable target [].DZIP3 is able to bind RNA through a Lys-rich region, which enhances its ubiquitination activity. It is suggested that RNA-binding proteins or ribonucleoprotein particles (RNPs) might be physiological targets for this enzyme, which could be important during viral infections as the ubiquitin process also mediates virus budding, especially for those replicating through RNA intermediates [].
CRIK (also called citron kinase) is an effector of the small GTPase Rho. It plays an important function during cytokinesis and affects its contractile process []. CRIK-deficient mice show severe ataxia and epilepsy as a result of abnormal cytokinesis and massive apoptosis in neuronal precursors []. A Down syndrome critical region protein TTC3 interacts with CRIK and inhibits CRIK-dependent neuronal differentiation and neurite extension [].CRIK contains a catalytic domain, a central coiled-coil domain, and a C-terminal region containing a Rho-binding domain (RBD), a zinc finger, and a pleckstrin homology (PH) domain, in addition to other motifs.
