Title

Enhanced casein kinase II activity in COS-1 cells upon overexpression of either its catalytic or noncatalytic subunit

UMMS Affiliation

Program in Molecular Medicine; Department of Biochemistry and Molecular Biology

Date

8-5-1991

Document Type

Article

Subjects

Amino Acid Sequence; Blotting, Northern; Blotting, Western; Casein Kinases; Catalysis; Cell Line; Cloning, Molecular; Cytomegalovirus; DNA; Gene Amplification; Genes, Viral; Molecular Sequence Data; Promoter Regions (Genetics); Protein Kinases; RNA; Transfection

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

Casein kinase II consists of catalytic (alpha) and regulatory (beta) subunits complexed into a heterotetrameric alpha 2 beta 2 structure. Full-length cDNAs encoding the alpha and beta subunits of human casein kinase II were subcloned into an expression vector containing the cytomegalovirus promotor, yielding the expression constructs pCMV-alpha and pCMV-beta. Northern analyses of total cellular RNA prepared from COS-1 fibroblasts 65 h after transfection with pCMV-alpha or pCMV-beta or with both expression constructs showed marked specific increases in corresponding alpha and beta subunit RNAs. Immunoblot analysis utilizing anti-casein kinase II antiserum of cytosolic extracts prepared from COS-1 cells co-transfected with pCMV-alpha and pCMV-beta showed 2- and 4-fold increases in immunoreactive alpha and beta subunit protein, respectively, relative to vector-transfected cells. These same cytosolic fractions exhibited an average 5-fold increase in casein kinase II catalytic activity. COS-1 cells transfected with pCMV-alpha alone exhibited a 3-fold increase in immunoreactive alpha subunit protein and a nearly 2-fold increase in cytosolic casein kinase II catalytic activity. Transfection with the cDNA coding for the noncatalytic beta subunit alone also caused a near doubling of cytosolic casein kinase II catalytic activity. No increase in immunoreactive alpha subunit protein was observed in pCMV-beta-transfected cells, and no increase in immunoreactive beta subunit protein was observed in pCMV-alpha-transfected cells. These results indicate that a portion of the endogenous cellular casein kinase II protein is not fully active and that raising the concentration of the alpha or beta subunit stimulates this latent activity.

Rights and Permissions

Citation: J Biol Chem. 1991 Aug 5;266(22):14435-9.

Related Resources

Link to Article in PubMed

Journal Title

The Journal of biological chemistry

PubMed ID

1713582