Birgitte B. Olsen, Jørgen Petersen, Olaf-Georg Issinger
BID, an interaction partner of protein kinase CK2?
Recombinant murine BID protein was used as an in vitro substrate for the CK2 holoenzyme and the catalytic CK2? subunit. The results obtained show that BID can only serve as a substrate for the catalytic CK2? subunit. Phosphorylation of BID using the CK2 holoenzyme was only possible in the presence of polylysine, supporting the notion that BID behaves similarly to calmodulin. Co-immunoprecipitation of BID and CK2 subunits revealed that BID is preferentially associated with the CK2? subunit. Enzyme kinetic analyses yielded a Km value for BID that is a level of magnitude lower than that measured for casein and the synthetic peptide, suggesting more specific and tight binding of BID to CK2?. In contrast are the Vmax values observed, with a significantly higher phosphorylation rate measured for casein and the synthetic peptide than for BID. When BID was phosphorylated by polylysine-stimulated CK2 holoenzyme prior to caspase-8 cleavage, the formation of tC-BID was reduced in comparison to treatment with caspase-8 in the absence of protein kinase. Mass spectrometric analysis of BID phosphorylated by CK2? before and after cleavage with caspase-8 showed phosphorylation of residues Thr58 and Ser76.
Biological Chemistry, Walter de Gruyter
Print ISSN: 1431-6730
Volume: 387, 04/2006
Pages: 441 - 449
Show full article (external site)
Show all available items of this journal
Search
