Mj. Hubbard et Nj. Mchugh, CALBINDIN(28KDA) (CALRETININ) ARE SUBSTANTIALLY LOCALIZED IN AND CALBINDIN(30KDA) THE PARTICULATE FRACTION OF RAT-BRAIN, FEBS letters, 374(3), 1995, pp. 333-337
Calbindin(28kDa) is implicated in cytosolic calcium transport and calc
ioprotection functions, principally as a mobile calcium buffer. Using
immunoblotting, we have found that 36% of total calbindin(28kDa) is in
the particulate fraction of rat brain. Particulate calbindin(28kDa) w
as located both within and outside organelles and required detergent f
or solubilisation. Equivalent observations were made for calbindin(30k
Da), 27% of which was insoluble. These findings indicate that a substa
ntial proportion of calbindin does not function as a mobile calcium bu
ffer, and perhaps instead has a calcium signalling role through target
ligands in the insoluble cellular fraction.