Calsyntenin 2 (CLSTN2)

The deduced 955-amino acid protein contains an N-terminal signal sequence, followed by 2 cadherin repeats, a C-terminal transmembrane domain, and a cytoplasmic C terminus.

CLSTN2 shares 58% amino acid identity with CLSTN1 and 94% identity with its mouse homolog. Northern blot analysis of human tissues detected a 5-kb transcript expressed exclusively in brain. In situ hybridization showed nonuniform Clstn2 expression in the majority of adult mouse brain regions. In cerebral cortex, Clstn2 was found in the somas and neuropil of all layers, with highest immunoreactivity in cortical layers 5 and 6. Immunoelectron microscopy showed that Clstn2 was prominently expressed in postsynaptic specializations of asymmetric synapses.