Caveolin-2 Localizes to the Golgi Complex but Redistributes to Plasma Membrane, Caveolae, and Rafts when Co-expressed with Caveolin-1

doi:10.1074/jbc.274.36.25708

Caveolin-2 Localizes to the Golgi Complex but Redistributes to Plasma Membrane, Caveolae, and Rafts when Co-expressed with Caveolin-1*

From the ^‡Dyson Vision Research Institute, Department of Ophthalmology, and Department of Cell Biology, Weill Medical College of Cornell University, New York 10021, the ^‖Renal Unit and Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02129, and the Departments of ^**Molecular Pharmacology and ^§Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461

Abstract

We have characterized comparatively the subcellular distributions of caveolins-1 and -2, their interactions and their roles in caveolar formation in polarized epithelial cells. In Fischer rat thyroid (FRT) cells, which express low levels of caveolin-2 and no caveolin-1, caveolin-2 localizes exclusively to the Golgi complex but is partially redistributed to the plasma membrane upon co-expression of caveolin-1 by transfection or by adenovirus-mediated transduction. In Madin-Darby canine kidney (MDCK) cells, which constitutively express both caveolin-1 and -2, caveolin-2 localized to both the Golgi complex and to the plasma membrane, where it co-distributed with caveolin-1 in flat patches and in caveolae. In FRT cells, endogenous or overexpressed caveolin-2 did not associate with low density Triton insoluble membranes that floated in sucrose density gradients but was recruited to these membranes when co-expressed together with caveolin-1. In MDCK cells, both caveolin-1 and caveolin-2 associated with low density Triton-insoluble membranes. In FRT cells, transfection of caveolin-1 promoted the assembly of plasma membrane caveolae that localized preferentially (over 99%) to the basolateral surface, like constitutive caveolae of MDCK cells. In contrast, as expected from its intracellular distribution, endogenous or overexpressed caveolin-2 did not promote the assembly of caveolae; rather, it appeared to promote the assembly of intracellular vesicles in the peri-Golgi area. The data reported here demonstrate that caveolin-1 and -2 have different and complementary subcellular localizations and functional properties in polarized epithelial cells and suggest that the two proteins co-operate to carry out specific as yet unknown tasks between the Golgi complex and the cell surface.

Footnotes

↵* This work was supported by R01 Grants GM41771 and GM34107 from the National Institutes of Health and by a Jules and Doris Stein Professorship from the Research to Prevent Blindness Foundation (to E. R.-B.).The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¶ Supported by a grant from Pfizer Corp., a pilot grant from the Einstein Diabetes Research and Training Center, and a research grant from the American Diabetes Association.
↵‡ Supported by NCI, National Institutes of Health Grant R01-CA-80250 and grants from the Charles E. Culpeper Foundation, the G. Hardd and Leila Y. Mathers Charitable Foundation, and the Sidney Kimmel Foundation for Cancer Research.
↵§§ To whom correspondence should be addressed: Weill Medical College of Cornell University, Dyson Vision Research Institute-LC300, 1300 York Ave., New York, NY 10021. Fax: 212-746-8101; E-mail: boulan@mail.med.cornell.edu.
Abbreviations:

MDCK

Madin-Darby canine kidney

CHAPS

3[(3-cholamidopropyldimethyl-ammonio]-2-hydroxypropanesulfonate

FRT

Fischer rat thyroid

LDTIM

low density Triton-insoluble membranes

mAb

monoclonal antibody

pAb

polyclonal antibody

PBS

phosphate-buffered saline, pH 7.4

TGN

trans-Golgi network

Mes

4-morpholineethanesulfonic acid
- Received April 14, 1999.
- Revision received June 15, 1999.
The American Society for Biochemistry and Molecular Biology, Inc.