Different properties of four molecular forms of protein kinase CK2 from Saccharomyces cerevisiae

CK2 is a pleiotropic constitutively active serine/threonine protein kinase composed of two catalytic α- and two regulatory β-subunits, whose regulation is still not well understood. It seems to play an essential role in regulation of many cellular processes. Four active forms of CK2, composed of αα′ββ′, α₂ββ′ , α′₂ββ′, and a free α′- subunit were isolated from wild-type yeast and strains containing a single deletion of the catalytic subunit. Each species exhibits properties typical for CK2, but they differ in substrate specificity and sensitivity to inhibitors. This suggests that each CK2 isomer may regulate different process or may differ in the way of its regulation.