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J. Cell Biol.,
Volume 145, Number 7, June 28, 1999 1443-1459

* Centre for Microscopy and Microanalysis, Department of Physiology and Pharmacology, and Centre for Molecular and
Cellular Biology, University of Queensland, Brisbane, Queensland 4072, Australia; and Caveolins are integral membrane proteins
which are a major component of caveolae. In addition,
caveolins have been proposed to cycle between intracellular compartments and the cell surface but the exact
trafficking route and targeting information in the caveolin molecule have not been defined. We show that antibodies against the caveolin scaffolding domain or
against the COOH terminus of caveolin-1 show a striking specificity for the Golgi pool of caveolin and do not
recognize surface caveolin by immunofluorescence. To
analyze the Golgi targeting of caveolin in more detail,
caveolin mutants were expressed in fibroblasts. Specific
mutants lacking the NH2 terminus were targeted to the
cis Golgi but were not detectable in surface caveolae.
Moreover, a 32-amino acid segment of the putative
COOH-terminal cytoplasmic domain of caveolin-3 was
targeted specifically and exclusively to the Golgi complex and could target a soluble heterologous protein,
green fluorescent protein, to this compartment. Palmitoylation-deficient COOH-terminal mutants showed
negligible association with the Golgi complex. This
study defines unique Golgi targeting information in the
caveolin molecule and identifies the cis Golgi complex
as an intermediate compartment on the caveolin cycling pathway.
European Molecular Biology
Laboratory, 69012 Heidelberg, Germany
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