This is the cytoplasmic C-terminal domain of clasyntenin (CLSTN) proteins 1, 2 and 3 (also known as Alcadein-alpha, gamma and beta). These are postsynaptic Ca2-binding proteins, evolutionarily conserved type I membrane proteins. CLSTN forms a complex with APP and X11-like that stabilizes both APP and CLSTN proteins metabolically. CLSTN strongly associates with kinesin-1 light chains (KLC1) that induce kinesin-1 association with vesicles and functions as a novel cargo in axonal anterograde transport [1]. This domain includes the WD motifs required for KLC1 interaction (although one WD motif is sufficient), and the NP motif [1].

1: The novel cargo Alcadein induces vesicle association of kinesin-1 motor components and activates axonal transport. Araki Y, Kawano T, Taru H, Saito Y, Wada S, Miyamoto K, Kobayashi H, Ishikawa HO, Ohsugi Y, Yamamoto T, Matsuno K, Kinjo M, Suzuki T; EMBO J. 2007;26:1475-1486. PMID:17332754