Cloning and Disruption of CKB1, the Gene Encoding the 38-kDa β Subunit of Saccharomyces cerevisiae Casein Kinase II (CKII)

Abstract

Saccharomyces cerevisiae casein kinase II (CKII) contains two distinct catalytic (alpha and alpha') and regulatory (beta and beta') subunits. We report here the isolation and disruption of the gene, CKB1, encoding the 38-kDa beta subunit. The predicted Ckb1 sequence includes the N-terminal autophosphorylation site, internal acidic domain, and potential metal binding motif (CPX3C-X22-CPXC) present in other beta subunits but is unique in that it contains two additional autophosphorylation sites as well as a 30-amino-acid acidic insert. CKB1 is located on the left arm of chromosome VII, approximately 33 kilobases from the centromere and does not correspond to any previously characterized genetic locus. Haploid and diploid strains lacking either or both beta subunit genes are viable, demonstrating that the regulatory subunit of CKII is dispensable in S. cerevisiae. Such strains exhibit wild type behavior with regard to growth on both fermentable and nonfermentable carbon sources, mating, sporulation, spore germination, and resistance to heatshock and nitrogen starvation, but are salt-sensitive. Salt sensitivity is specific for NaCl and LiCl and is not observed with KCl or agents which increase osmotic pressure alone. These data suggest a role for CKII in ion homeostasis in S. cerevisiae.

Protein kinase CK2 regulates CDC25B phosphatase activity

“…The relative 32 P incorporation in CDC25B, after 24-32 min incubation with monomeric CK2, represented only 33% of the phosphorylation level with heterotetrameric CK2. These results indicate that the presence of the b subunit of CK2 probably stimulates the kinase activity of the monomeric a subunit towards CDC25B, as it has previously been described for many CK2 substrates (Lin et al, 1991;Bidwai et al, 1992). They also support the hypothesis that b subunit is required to recognize CDC25B as a substrate.…”

Casein Kinase II Regulation of the Hot1 Transcription Factor Promotes Stochastic Gene Expression

“…Others have reported an undefined role for CK2 during salt stress (25,26,33). We have shed light on this CK2 function; however, the mechanisms that relieve CK2 inhibition of Hot1 remain unknown.…”

“…Regulated by CK2-Previous work has identified CK2 as a kinase required for cellular responses to salt stress (25). Deletion of the CK2 ␤ regulatory subunits results in growth sensitivities to Na ϩ and Liϩ (26); however, functions for CK2 in the response to salt stress remain largely unknown.…”

Phosphorylation of Yeast Plasma Membrane H+-ATPase by Casein Kinase I

“…These reports suggest a role for CK1 in signal transduction events. Unlike the cAMP-dependent protein kinase A or the multimeric CK2 (37,38), it appears unlikely that CK1 activity is regulated by a second messenger or through protein-protein interactions with other regulatory subunits. Brockman and Anderson (39) have reported a regulatory effect of phosphatidylinositol bisphosphate on the activity of the 37-kDa casein kinase I of red blood cells, although this result has been questioned by others (40).…”