Linked Life Data

8632005

Source:http://linkedlifedata.com/resource/pubmed/id/8632005

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
1996-7-2
pubmed:abstractText
Caveolae are flask-shaped plasma membrane specializations that are thought to exist in most cell types. A 22-kDa protein, caveolin, is an integral membrane component of caveolae membranes in vivo. Previous studies have demonstrated that caveolin is phosphorylated on tyrosine by oncogenic viral Src (v-Src) and that caveolin is physically associated as a hetero-oligomeric complex with normal cellular Src (c-Src) and other Src family tyrosine kinases. Caveolin contains eight conserved tyrosine residues that may serve as potential substrates for Src. Here, we have begun to study the phosphorylation of caveolin by Src family tyrosine kinases both in vitro and in vivo. Using purified recombinant components, we first reconstituted the phosphorylation of caveolin by Src kinase in vitro. Microsequencing of Src-phosphorylated caveolin revealed that phosphorylation occurs within the extreme N-terminal region of full-length caveolin between residues 6 and 26. This region contains three tyrosine residues at positions 6, 14, and 25. Deletion mutagenesis demonstrates that caveolin residues 1-21 are sufficient to support this phosphorylation event, implicating tyrosine 6 and/or 14. In vitro phosphorylation of caveolin-derived synthetic peptides and site-directed mutagenesis directly show that tyrosine 14 is the principal substrate for Src kinase. In support of these observations, tyrosine 14 is the only tyrosine residue within caveolin that bears any resemblance to the known recognition motifs for Src family tyrosine kinases. In order to confirm or refute the relevance of these in vitro studies, we next analyzed the tyrosine phosphorylation of endogenous caveolin in v-Src transformed NIH 3T3 cells. In vivo, two isoforms of caveolin are known to exist: alpha-caveolin contains residues 1-178 and beta-caveolin contains residues 32-178. Only alpha-caveolin underwent tyrosine phosphorylation in v-Src transformed NIH 3T3 cells, although beta-caveolin is well expressed in these cells. As beta-caveolin lacks residues 1-31 (and therefore tyrosine 14), these in vivo studies directly demonstrate the validity of our in vitro studies. Because alpha- and beta-caveolin are known to assume a distinct but overlapping subcellular distribution within a single cell, v-Src phosphorylation of alpha-caveolin may only affect a subpopulation of caveolae that contain alpha-caveolin.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
16
pubmed:volume
271
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3863-8
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:8632005-3T3 Cells, pubmed-meshheading:8632005-Amino Acid Sequence, pubmed-meshheading:8632005-Animals, pubmed-meshheading:8632005-Antibodies, pubmed-meshheading:8632005-Caveolin 1, pubmed-meshheading:8632005-Caveolins, pubmed-meshheading:8632005-Cloning, Molecular, pubmed-meshheading:8632005-Consensus Sequence, pubmed-meshheading:8632005-Dogs, pubmed-meshheading:8632005-Membrane Proteins, pubmed-meshheading:8632005-Mice, pubmed-meshheading:8632005-Molecular Sequence Data, pubmed-meshheading:8632005-Oncogene Protein pp60(v-src), pubmed-meshheading:8632005-Peptide Fragments, pubmed-meshheading:8632005-Phosphorylation, pubmed-meshheading:8632005-Protein-Tyrosine Kinases, pubmed-meshheading:8632005-Recombinant Fusion Proteins, pubmed-meshheading:8632005-Substrate Specificity
pubmed:year
1996
pubmed:articleTitle
Phosphorylation of caveolin by src tyrosine kinases. The alpha-isoform of caveolin is selectively phosphorylated by v-Src in vivo.
pubmed:affiliation
Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142-1479 and Research Genetics, Huntsville, Alabama 35801, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't