ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Abstract: The hypothesis that casein kinase II (CKII) is a microtubule-associated protein kinase was investigated using a neuronal cell line and bovine brain. Heparin, an inhibitor of CKII, inhibited the phosphorylation of a PC12 cytosolic protein whose molecular weight was similar to that of β-tubulin. Partially purified PC12 CKII was immunoreactive to an antibody directed against bovine CKII and was able to phosphorylate purified β-tubulin in a heparin-inhibitable manner when the concentration of tubulin was less than 50 μg/ml. To better determine if CKII is a microtubule-associated protein kinase, bovine brain tubulin was chromatographed on FPLC Mono Q and phosphocellulose columns. Several tubulin casein kinase (TCK) activities were apparent. All TCK activities phosphorylated tubulin and casein, but none was able to phosphorylate the CKII-specific synthetic peptide RRREEETEEE. One of these TCK fractions was immunoreactive to the antibody directed against CKII, and this antibody labeled a 50-kDa molecular mass band that had a molecular mass distinctly different from those of the subunits of CKII. Thus, we suggest that a CKII-like protein, but not CKII, might be a microtubule-associated protein.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1471-4159.1992.tb10089.x
