Identification of proteins that associate with protein kinase CK2.
In order to aid in an understanding of the cellular functions of protein kinase CK2, a search for interacting proteins was carried out using a 32P-labeled CK2 overlay method. Several proteins were found to associate with CK2 by this assay; among them, one protein of 110 kDa appeared to be the most prominent one. The possible association of CK2 with p110 was suggested by experiments involving the co-immunoprecipitation using anti-CK2 antibodies. Further analysis using GST-CK2 fusion proteins demonstrated that the CK2-p110 interaction occurred through the CK2alpha/alpha' subunits. To identify p110, it was purified using a GST-CK2 affinity column, and internal amino acid sequencing was then performed. p110 was found to be nucleolin, a nucleolar protein that may be important for rRNA synthesis; a possible role of CK2 in the control of this process is suggested. Using the same CK2 overlay technique, another interacting protein, insulin receptor substrate 1 (IRS-1), was also identified. By applying a modified overlay method using individual 35S-labeled CK2 subunits, obtained by in vitro translation in rabbit reticulate lysates, it was determined that CK2 associates with IRS-1 through its alpha/alpha' subunits; i.e. in keeping with the fact that IRS-1 is a known substrate for CK2. However, further work is needed to examine the association of CK2 with IRS-1 in vivo in order to fully understand the significance of the interaction.
Li
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Department of Pharmacology and Biochemistry, University of Washington, Seattle 98195, USA.
Dobrowolska
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Krebs
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EG
D016475:3T3 Cells; D000818:Animals; D047390:Casein Kinase II; D055504:Insulin Receptor Substrate Proteins; D051379:Mice; D010750:Phosphoproteins / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D000097796:Nucleolin
D047390:Casein Kinase II; D055504:Insulin Receptor Substrate Proteins; D010750:Phosphoproteins; D017346:Protein Serine-Threonine Kinases; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D000097796:Nucleolin; C526295:Irs1 protein, mouse; C526296:Irs1 protein, rat; C484552:Mark1 protein, rat