This domain is found at the N-terminus of proteins containing von Willebrand factor type A (VWA, Pfam:PF00092) and Cache (Pfam:PF02743) domains. It has been found in vertebrates, Drosophila and C. elegans but has not yet been identified in other eukaryotes. It is probably involved in the function of some voltage-dependent calcium channel subunits [1].

1: Ducky mouse phenotype of epilepsy and ataxia is associated with mutations in the Cacna2d2 gene and decreased calcium channel current in cerebellar Purkinje cells. Barclay J, Balaguero N, Mione M, Ackerman SL, Letts VA, Brodbeck J, Canti C, Meir A, Page KM, Kusumi K, Perez-Reyes E, Lander ES, Frankel WN, Gardiner RM, Dolphin AC, Rees M; J Neurosci 2001;21:6095-6104. PMID:11487633