Calmodulin (CaM) is a key mediator of calcium-dependent signalling and is subject to regulatory post-translational modifications, including trimethylation of Lys-115. In this paper, we identify a class I, non-SET domain protein methyltransferase, calmodulin-lysine N-methyltransferase (EC 18.104.22.168). A polypeptide chosen from a fraction enriched in calmodulin methyltransferase activity was trypsinized and analysed by tandem mass spectrometry. The amino-acid sequence obtained identified conserved, homologous proteins of unknown function across a wide range of species, thus implicating a broad role for lysine methylation in calcium-dependent signalling. Encoded by c2orf34, the human homologue is a component of two related multigene deletion syndromes in humans. Human, rat, frog, insect and plant homologues were cloned and Escherichia coli-recombinant proteins catalysed the formation of a trimethyllysyl residue at position 115 in CaM, as verified by product analyses and mass spectrometry.
|State||Published - 2010|
Bibliographical noteFunding Information:
Mass spectrometric analyses were performed by Dr C.M. Beach at the University of Kentucky, Center for Structural Biology Protein Core Facility. This core facility is supported in part by funds from the NIH National Center for Research Resources (NCRR) Grant P20 RR020171. The research reported here was supported by Department of Energy Grant DE-FG02-92ER20075 and Kentucky Science & Engineering Foundation Grant KSEF-1526-RDE-010 to R.L.H., and by NIH Grant R01 GM073839 to R.C.T. We are grateful to Dr R.E. Zielinski for providing the AtCaM2 clone and to Drs S.R. Palli and A.B. Downie for the cDNAs from Tribolium castaneum and Arabidopsis thaliana, respectively.
ASJC Scopus subject areas
- Chemistry (all)
- Biochemistry, Genetics and Molecular Biology (all)
- Physics and Astronomy (all)