RGD Reference Report - Molecular cloning of the p45 subunit of pyruvate dehydrogenase kinase. - Rat Genome Database

Send us a Message



Submit Data |  Help |  Video Tutorials |  News |  Publications |  Download |  REST API |  Citing RGD |  Contact   

Molecular cloning of the p45 subunit of pyruvate dehydrogenase kinase.

Authors: Popov, KM  Kedishvili, NY  Zhao, Y  Gudi, R  Harris, RA 
Citation: Popov KM, etal., J Biol Chem 1994 Nov 25;269(47):29720-4.
RGD ID: 68683
Pubmed: PMID:7961963   (View Abstract at PubMed)

Purified preparations of rat heart pyruvate dehydrogenase kinase have two polypeptides with molecular weights of 48,000 (p48) and 45,000 (p45). Recently, we reported the primary structure of p48 (Popov, K. M., Kedishvili, N. Y., Zhao, Y., Shimomura, Y., Crabb, D. W., and Harris, R. A. (1993) J. Biol. Chem. 268, 26602-26606) and presented evidence that (i) it exhibits kinase activity for pyruvate dehydrogenase and (ii) it belongs to a family of mitochondrial protein kinases unique from other eukaryotic protein kinases. Here, we report the molecular cloning and deduced amino acid sequence of p45. The protein sequence of p45 has 70% identity to the protein sequence of p48. Minor differences exist throughout the protein sequences with the greatest difference occurring at the amino termini. Recombinant p45 protein, expressed in Escherichia coli and purified to homogeneity, catalyzed the phosphorylation and inactivation of kinase-depleted pyruvate dehydrogenase complex, indicating that p45 and p48 correspond to different isoforms of pyruvate dehydrogenase kinase. Northern blot analysis revealed a single hybridizing species of 2.5 kilobases. The highest level of p45 message expression was found in heart and skeletal muscle and the lowest in spleen and lung. Liver, kidney, brain, and testis express intermediate amounts of p45 mRNA. In contrast, p48 mRNA is predominantly expressed in heart, with other tissues expressing only a modest amount of this message. Tissue-specific expression of isoforms of pyruvate dehydrogenase kinase may indicate the existence of tissue-specific mechanisms for the regulation of pyruvate dehydrogenase activity.

Objects referenced in this article
Gene Pdk2 pyruvate dehydrogenase kinase 2 Rattus norvegicus

Additional Information