This Article Full Text (PDF) Other Versions of this Article: JB.00710-06v1 189/1/109    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Soo, P.-C. Articles by Lai, H.-C. Search for Related Content PubMed PubMed Citation Articles by Soo, P.-C. Articles by Lai, H.-C.

 Previous Article  |  Next Article 

J. Bacteriol. doi:10.1128/JB.00710-06
Copyright (c) 2006, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.

Pirin regulates pyruvate catabolism through interaction with the pyruvate dehydrogenase E1 subunit and modulating pyruvate dehydrogenase activity

Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan, R.O.C; Department of Laboratory Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan, R.O.C; Department of Laboratory Medicine and Biotechnology, College of Medicine, Tzu Chi University, Hualien, Taiwan

^* To whom correspondence should be addressed. Email: hclai{at}ha.mc.ntu.edu.tw.

	Abstract

The protein Pirin, which is involved in a variety of biological processes, is conserved from prokaryotic micro-organisms, fungi, and plants to mammals. It acts as a transcriptional cofactor or an apoptosis-related protein in mammals, and involves seed germination and seedling development in plants. In prokaryotes, while Pirin is stress-induced in cyanobacteria and may act as a quercetinase in Escherichia coli, the functions of Pirin orthologs remain mostly uncharacterized. We show that the Serratia marcescens pirin_Sm gene encodes an ortholog of Pirin protein. Protein pull-down and bacterial two-hybrid assays followed by SDS-PAGE and electrospray ionization (ESI) MASS-MASS analyses showed the pyruvate dehydrogenase (PDH) E1 subunit as a component interacting with Pirin_Sm. Functional analyses showed that both PDH E1 subunit activity and PDH enzyme complex activity are inhibited by Pirin_Sm in S. marcescens CH-1. The S. marcescens CH-1 pirin_Sm gene was subsequently mutated by insertion-deletion homologous recombination. Accordingly, the PDH E1, PDH enzyme complex activities and cellular ATP concentration increased up to 250%, 140%, and 220%, respectively, in the S. marcescens CH-1 pirin_Sm mutant. Concomitantly, the cellular NADH/NAD⁺ ratio increased in the pirin_Sm mutant, indicating increased tricarboxylic acid (TCA) cycle activity. Our results show that Pirin_Sm plays a regulatory role in the process of pyruvate catabolism to acetyl-CoA through interaction with the PDH E1 subunit and inhibiting PDH enzyme complex activity in S. marcescens CH-1, and suggest Pirin_Sm is an important protein involved in determining the direction of pyruvate metabolism to go towards either the TCA cycle or the fermentation pathways.

This article has been cited by other articles:

• Ristorcelli, E., Beraud, E., Verrando, P., Villard, C., Lafitte, D., Sbarra, V., Lombardo, D., Verine, A. (2008). Human tumor nanoparticles induce apoptosis of pancreatic cancer cells. FASEB J. 22: 3358-3369 [Abstract] [Full Text]