We previously reported the ability of protein disulfide isomerase (PDI) to undergo an ATP-dependent autophosphorylation. Our efforts to map the modification site have been hindered by the low abundance and instability of the labeling. Results are presented in this paper on the nature of phospho-PDI, which appears as an intermediate with a half-life of 2.5-8.8 min in an ATPase reaction. ATP binds to PDI with high affinity, K9.66 µM, and the kinetic parameters K and k of the ATPase reaction were measured by using a pyruvate kinase-lactate dehydrogenase-coupled assay under various conditions. Strikingly, the ATPase reaction is stimulated in the presence of denatured polypeptides, while the disulfide oxidization activity of PDI is not affected by ATP. However, PDI is known to participate in various unrelated functions in the endoplasmic reticulum, and ATP could be involved in the regulation of one of these. The results are discussed in light of recent findings on ATP-chaperone relationships.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				O. Ben-Zeev, H. Z. Mao, and M. H. Doolittle Maturation of Lipoprotein Lipase in the Endoplasmic Reticulum. CONCURRENT FORMATION OF FUNCTIONAL DIMERS AND INACTIVE AGGREGATES J. Biol. Chem., March 15, 2002; 277(12): 10727 - 10738. [Abstract] [Full Text] [PDF]

				P. Y. Cheung and J. E. Churchich Recognition of Protein Substrates by Protein-disulfide Isomerase. A SEQUENCE OF THE b' DOMAIN RESPONDS TO SUBSTRATE BINDING J. Biol. Chem., November 12, 1999; 274(46): 32757 - 32761. [Abstract] [Full Text] [PDF]

				P. S. Kim and P. Arvan Endocrinopathies in the Family of Endoplasmic Reticulum (ER) Storage Diseases: Disorders of Protein Trafficking and the Role of ER Molecular Chaperones Endocr. Rev., April 1, 1998; 19(2): 173 - 202. [Abstract] [Full Text]

				T. P. Primm, K. W. Walker, and H. F. Gilbert Facilitated Protein Aggregation. EFFECTS OF CALCIUM ON THE CHAPERONE AND ANTI-CHAPERONE ACTIVITY OF PROTEIN DISULFIDE-ISOMERASE J. Biol. Chem., December 27, 1996; 271(52): 33664 - 33669. [Abstract] [Full Text] [PDF]

				E. F. Corbett, K. M. Michalak, K. Oikawa, S. Johnson, I. D. Campbell, P. Eggleton, C. Kay, and M. Michalak The Conformation of Calreticulin Is Influenced by the Endoplasmic Reticulum Luminal Environment J. Biol. Chem., August 25, 2000; 275(35): 27177 - 27185. [Abstract] [Full Text] [PDF]

				A. Menoret, Z. Li, M. L. Niswonger, A. Altmeyer, and P. K. Srivastava An Endoplasmic Reticulum Protein Implicated in Chaperoning Peptides to Major Histocompatibility of Class I Is an Aminopeptidase J. Biol. Chem., August 31, 2001; 276(36): 33313 - 33318. [Abstract] [Full Text] [PDF]