JCB logo
Accuri Cytometers
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents
This Article
Right arrow Full Text
Right arrow Full Text (PDF, 519K)
Right arrow PPT slides of all figures
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JCB
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Jones, S. M.
Right arrow Articles by Howell, K. E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Jones, S. M.
Right arrow Articles by Howell, K. E.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Facebook   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

© The Rockefeller University Press, 0021-9525/1997//339 $5.00
The Journal of Cell Biology, Volume 139, Number 2, , 1997 339-349

Article

Phosphatidylinositol 3–Kinase Is Required for the Formation of Constitutive Transport Vesicles from the TGN



Steven M. Jones and Kathryn E. Howell

Department of Cellular and Structural Biology, University of Colorado School of Medicine, Denver, Colorado 80262

An 85-kD cytosolic complex (p62cplx), consisting of a 62-kD phosphoprotein (p62) and a 25-kD GTPase, has been shown to be essential for the cell-free reconstitution of polymeric IgA receptor (pIgA-R)-containing exocytic transport vesicle formation from the TGN (Jones, S.M., J.R. Crosby, J. Salamero, and K.E. Howell. 1993. J. Cell Biol. 122:775–788). Here the p62cplx is identified as a regulatory subunit of a novel phosphatidylinositol 3–kinase (PI3-kinase). This p62cplx-associated PI3-kinase activity is stimulated by activation of the p62cplx-associated GTPase, and is specific for phosphatidylinositol (PI) as substrate, and is sensitive to wortmannin at micromolar concentrations. The direct role of this p62cplx-associated PI3-kinase activity in TGN-derived vesicle formation is indicated by the finding that both lipid kinase activity and the formation of pIgA-R–containing exocytic vesicles from the TGN are inhibited by wortmannin with similar dose-response curves and 50% inhibitory concentrations (3.5 µM). These findings indicate that phosphatidylinositol-3-phosphate (PI[3]P) is required for the formation of TGN-derived exocytic transport vesicles, and that the p62cplx-associated PI3-kinase and an activated GTPase are the essential molecules that drive production of this PI(3)P.

Abbreviations used in this paper: Cyt, cytosol; GTP{gamma}S, guanosine-5'-O- (3-thiophosphate); IC50, 50% inhibitory concentration; PI, phosphatidylinositol; PI(3)P, phosphatatidylinositol-3-phosphate; PI(4)P, phosphatidylinositol-4-phosphatate; PI(4,5)P2, phosphatidylinositol-4,5-diphosphate; pIgA-R, polymeric IgA receptor; PI3-kinase, phosphatidylinositol 3-kinase; PNS, postnuclear supernatant; SGF, stacked Golgi fraction.

Address all correspondence to K.E. Howell, Department of Cellular and Structural Biology, University of Colorado School of Medicine, Denver, CO 80262. Tel.: (303) 315-5153. Fax: (303) 315-4729. E-mail: kathryn.howell{at}uchsc.edu


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Facebook Facebook   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?


This article has been cited by other articles:



  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents