Calbindin(28kDa) is specifically associated with extranuclear constituents of the dense particulate fraction

Abstract

Recent attempts to understand the function of calbindin(28kDa), a widely expressed calcium-binding protein, are confounded by uncertainties over its subcellular location. Using immunoblot analysis of rat brain subregions, we found that the proportion of particulate calbindin(28kDa) (24-43% of total) was independent of expression level and location. The association of calbindin(28kDa) with particulate structures appeared to be specific, since it persisted when soluble calbindin(28kDa) was sequestered by antibodies added before tissue disruption. Moreover, when exogenous calbindin(28kDa) was added during homogenisation of brain from calbindin(28kDa)-nullmutant mice, only 10% partitioned to the..