Kaptin (Kptn) is an actin-associated protein that may be involved in the actin organisation in platelets and neurons [, , ]. Mutations in the kaptin gene cause mental retardation, autosomal recessive 41 (MRT41) []. Kaptin is a component of the KICSTOR complex which is found in the lysosome and interacts with the GATOR1 complex, binding it to the lysosomal membrane surface. KICSTOR is a negative regulator of mTORC1 signalling during amino acid or glucose starvation [].
