Identification of a novel CoA synthase isoform, which is primarily expressed in the brain.
CoA and its derivatives Acetyl-CoA and Acyl-CoA are important players in cellular metabolism and signal transduction. CoA synthase is a bifunctional enzyme which mediates the final stages of CoA biosynthesis. In previous studies, we have reported molecular cloning, biochemical characterization, and subcellular localization of CoA synthase (CoASy). Here, we describe the existence of a novel CoA synthase isoform, which is the product of alternative splicing and possesses a 29aa extension at the N-terminus. We termed it CoASy beta and originally identified CoA synthase, CoASy alpha. The transcript specific for CoASy beta was identified by electronic screening and by RT-PCR analysis of various rat tissues. The existence of this novel isoform was further confirmed by immunoblot analysis with antibodies directed to the N-terminal peptide of CoASy beta. In contrast to CoASy alpha, which shows ubiquitous expression, CoASy beta is primarily expressed in the brain. Using confocal microscopy, we demonstrated that both isoforms are localized on mitochondria. The N-terminal extension does not affect the activity of CoA synthase, but possesses a proline-rich sequence which can bring the enzyme into complexes with signalling proteins containing SH3 or WW domains. The role of this novel isoform in CoA biosynthesis, especially in the brain, requires further elucidation.
Nemazanyy
Ivan
I
Department of Structure and Function of Nucleic Acids, Institute of Molecular Biology and Genetics, 150 Zabolotnogo St, Kyiv 03680, Ukraine. nemazanyy@imbg.org.ua
Panasyuk
Ganna
G
Breus
Oksana
O
Zhyvoloup
Alexander
A
Filonenko
Valeriy
V
Gout
Ivan T
IT
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000201:enzymology*; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis; D051379:Mice; D008928:Mitochondria / Q000201:enzymology; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D014166:Transferases / Q000096:biosynthesis*
D007527:Isoenzymes; D014166:Transferases; C509687:COASY protein, human