This is a family of apparent calmodulin-binding proteins found at high levels in the testis and vomeronasal organ and at lower levels in certain other tissues [1]. Enkurin is a scaffold protein that binds PI3 kinase to sperm transient receptor potential (canonical) (TRPC) channels. The mammalian transient receptor potential (canonical) channels are the primary candidates for the Ca(2+) entry pathway activated by the hormones, growth factors, and neurotransmitters that exert their effect through activation of PLC [2]. Calmodulin binds to the C-terminus of all TRPC channels, and dissociation of calmodulin from TRPC4 results in profound activation of the channel [3].

1: Enkurin is a novel calmodulin and TRPC channel binding protein in sperm. Sutton KA, Jungnickel MK, Wang Y, Cullen K, Lambert S, Florman HM; Dev Biol. 2004;274:426-435. PMID:15385169

2: Protein-protein interaction and functionTRPC channels. Kiselyov K, Kim JY, Zeng W, Muallem S; Pflugers Arch. 2005;451:116-124. PMID:16044307

3: Regulating the acrosome reaction. Florman HM, Jungnickel MK, Sutton KA; Int J Dev Biol. 2008;52:503-510. PMID:18649263