Calpain 7 (CAPN7)

The deduced 814-amino acid human protein contains a calpain-like cysteine protease domain and a C-terminal PBH domain. Northern blot analysis revealed wide expression of a 3.8-kb CAPN7 transcript. Expression was strong in pancreas, moderate in skeletal muscle, liver, and placenta, and weak in kidney, lung, brain, and heart. Western blot analysis detected expression of a 92-kD protein. Immunofluorescence microscopy demonstrated nuclear expression of CAPN7, unlike other calpains. Functional analysis could not demonstrate complementation in mutant yeast or activity against conventional calpain substrates. The function of CAPN7 encoded by this gene is not known. An orthologue has been found in mouse but it seems to diverge from other family members. The mouse orthologue is thought to be calcium independent with protease activity.