Complexin 4 (CPLX4)

By searching genomic databases for CPX-like sequences, followed by PCR of a brain cDNA library, Reim et al. (2005) cloned CPLX4, which they designated CPX IV. The deduced 160-amino acid protein has a calculated molecular mass of 18.3 kD. CPX IV contains a C-terminal CAAX box motif for posttranslational prenylation. CPX IV shares more than 91% amino acid identity with mouse Cpx IV. Northern blot analysis of mouse and rat tissues detected Cpx IV only in retina, and database analysis indicated that mouse Cpx IV is expressed only in eye and retina. Immunohistochemical analysis of mouse retina detected Cpx IV expression restricted to rod photoreceptors, where it localized to ribbon synapses but not to conventional synapses.