GAIP, a Galpha(i-3)-binding protein, is associated with Golgi-derived vesicles and protein trafficking

Wylie, Fiona, Heimann, Kirsten R., Luan Le, Tam, Brown, Darren, Rabnott, Glenn C. and Stow, Jennifer (1999) GAIP, a Galpha(i-3)-binding protein, is associated with Golgi-derived vesicles and protein trafficking. American Journal of Physiology, 276 2: C497-C506.


Author Wylie, Fiona
Heimann, Kirsten R.
Luan Le, Tam
Brown, Darren
Rabnott, Glenn C.
Stow, Jennifer
Title GAIP, a Galpha(i-3)-binding protein, is associated with Golgi-derived vesicles and protein trafficking
Formatted title
GAIP, a Gαi-3-binding protein, is associated with Golgi-derived vesicles and protein trafficking
Journal name American Journal of Physiology   Check publisher's open access policy
ISSN 0363-6143
1522-1563
Publication date 1999-02-01
Sub-type Article (original research)
Volume 276
Issue 2
Start page C497
End page C506
Total pages 10
Place of publication Bethesda, MD, U.S.A.
Publisher American Physiologial Society
Language eng
Subject C1
270103 Protein Targeting and Signal Transduction
730102 Immune system and allergy
Formatted abstract
Proteins of the regulators of G protein signaling (RGS) family bind to Gα subunits to downregulate their signaling in a variety of systems. Gα-interacting protein (GAIP) is a mammalian RGS protein that shows high affinity for the activated state of Gαi-3, a protein known to regulate post-Golgi trafficking of secreted proteins in kidney epithelial cells. This study aimed to localize GAIP in epithelial cells and to investigate its potential role in the regulation of membrane trafficking. LLC-PK1 cells were stably transfected with a c-myc-tagged GAIP cDNA. In the transfected and untransfected cells, GAIP was found in the cytosol and on cell membranes. Immunogold labeling showed that membrane-bound GAIP was localized on budding vesicles around Golgi stacks. When an in vitro assay was used to generate vesicles from isolated rat liver and Madin-Darby canine kidney cell Golgi membranes, GAIP was found to be concentrated in fractions of newly budded Golgi vesicles. Finally, the constitutive trafficking and secretion of sulfated proteoglycans was measured in cell lines overexpressing GAIP. We show evidence for GAIP regulation of secretory trafficking before the level of the trans-Golgi network but not in post-Golgi secretion. The location and functional effects of GAIP overlap only partially with those of Gαi-3 and suggest multiple roles for GAIP in epithelial cells.
Copyright © 1999 the American Physiological Society
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collection: Institute for Molecular Bioscience - Publications
 
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Created: Wed, 11 Jun 2008, 01:23:49 EST