title: Cysteine3 of Src family protein tyrosine kinase determines palmitoylation and localization in caveolae.
abstract: Recent work has demonstrated that p56lck, a member of the Src family of protein tyrosine kinases (PTKs), is modified by palmitoylation of a cysteine residue(s) within the first 10 amino acids of the protein (in addition to amino-terminal myristoylation that is a common modification of the Src family of PTKs). This is now extended to three other members of this family by showing incorporation of [3H]palmitate into p59fyn, p55fgr, and p56hck, but not into p60src. The [3H]palmitate was released by treatment with neutral hydroxylamine, indicating a thioester linkage to the protein. Individual replacement of the two cysteine residues within the first 10 amino acids of p59fyn and p56lck with serine indicated that Cys3 was the major determinant of palmitoylation, as well as association of the PTK with glycosyl-phosphatidylinositol-anchored proteins. Introduction of Cys3 into p60src led to its palmitoylation. p59fyn but not p60src partitioned into Triton-insoluble complexes that contain caveolae, microinvaginations of the plasma membrane. Mapping of the requirement for partitioning into caveolae demonstrated that the amino-terminal sequence Met-Gly-Cys is both necessary and sufficient within the context of a Src family PTK to confer localization into caveolae. Palmitoylation of this motif in p59fyn also modestly increased its overall avidity for membranes. These results highlight the role of the amino-terminal motif Met-Gly-Cys in determining the structure and properties of members of the Src family of PTKs.
authors.affiliation: Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110.
authors.forename: A M
authors.initials: AM
authors.lastname: Shenoy-Scaria
authors.forename: D J
authors.initials: DJ
authors.lastname: Dietzen
authors.forename: J
authors.initials: J
authors.lastname: Kwong
authors.forename: D C
authors.initials: DC
authors.lastname: Link
authors.forename: D M
authors.initials: DM
authors.lastname: Lublin
mesh_terms: D000215:Acylation; D000595:Amino Acid Sequence; D015703:Antigens, CD / Q000032:analysis / Q000378:metabolism; D001798:Blood Proteins / Q000032:analysis / Q000378:metabolism; D018958:CD55 Antigens; D051242:Caveolin 1; D022461:Caveolins; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D003545:Cysteine / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D008562:Membrane Glycoproteins / Q000032:analysis / Q000378:metabolism; D008565:Membrane Proteins / Q000032:analysis; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009226:Myristates / Q000378:metabolism; D010168:Palmitates / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D051076:Proto-Oncogene Proteins c-fyn; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism
chemical_list: D015703:Antigens, CD; D001798:Blood Proteins; D018958:CD55 Antigens; D051242:Caveolin 1; D022461:Caveolins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009226:Myristates; D010168:Palmitates; D011518:Proto-Oncogene Proteins; D011505:Protein-Tyrosine Kinases; C494957:FYN protein, human; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D051076:Proto-Oncogene Proteins c-fyn; D016392:Proto-Oncogene Proteins pp60(c-src); D003545:Cysteine