Molecular characterization of recombinant mouse adenosine kinase and evaluation as a target for protein phosphorylation

Bogachan Sahin, Janice W. Kansy, Angus C. Nairn, Jozef Spychala, Steven E. Ealick, Allen A. Fienberg, Robert W. Greene, James A. Bibb

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

The regulation of adenosine kinase (AK) activity has the potential to control intracellular and interstitial adenosine (Ado) concentrations. In an effort to study the role of AK in Ado homeostasis in the central nervous system, two isoforms of the enzyme were cloned from a mouse brain cDNA library. Following overexpression in bacterial cells, the corresponding proteins were purified to homogeneity. Both isoforms were enzymatically active and found to possess Km and Vmax values in agreement with kinetic parameters described for other forms of AK. The distribution of AK in discrete brain regions and various peripheral tissues was defined. To investigate the possibility that AK activity is regulated by protein phosphorylation, a panel of protein kinases was screened for ability to phosphorylate recombinant mouse AK. Data from these in vitro phosphorylation studies suggest that AK is most likely not an efficient substrate for PKA, PKG, CaMKII, CK1, CK2, MAPK, Cdk1, or Cdk5. PKC was found to phosphorylate recombinant AK efficiently in vitro. Further analysis revealed, however, that this PKC-dependent phosphorylation occurred at one or more serine residues associated with the N-terminal affinity tag used for protein purification.

Original languageEnglish (US)
Pages (from-to)3547-3555
Number of pages9
JournalEuropean Journal of Biochemistry
Volume271
Issue number17
DOIs
StatePublished - Sep 1 2004

Keywords

  • Adenosine kinase
  • Adenosine regulation
  • CNS
  • Protein serine/threonine kinases

ASJC Scopus subject areas

  • Biochemistry

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