Adenylate Kinase 7 (AK7)

Adenylate kinase 7 is a differentiation marker of kinocilia-bearing cells. Since a fusion protein of pAK7 and green fluorescent protein exhibited no measurable adenylate kinase activity when expressed in HEK 293T cells, the 82 kDa pAK7 protein probably is not really an adenylate kinase, but must have other functions. The time course of pAK7 mRNA and protein levels during development of rat testis and ependymal primary cultures parallels the expression of kinocilia. The protein may therefore be considered as an ependymal differentiation marker involved in ciliogenesis. A yeast two-hybrid screen was employed to gain leads on possible functions of pAK7 not related to adenylate kinase activity. pAK7 is exclusively produced in rat tissues known for the presence of kinocilia, namely testis, lung and ependyma, as determined by real-time RT-PCR.