title: Association of Src-family protein tyrosine kinases with sphingolipids in rat cerebellar granule cells differentiated in culture.
abstract: Src family kinases play a relevant role in the development and differentiation of neuronal cells. They are abundant in sphingolipid-enriched membrane domains of many cell types, and these domains are hypothesized to function in bringing together molecules important to signal transduction. We studied the association of Src family tyrosine kinases and their negative regulatory kinase, Csk, with sphingolipids in sphingolipid-enriched domains of rat cerebellar granule cells differentiated in culture. We find that c-Src, Lyn and Csk are enriched in the sphingolipid-enriched fraction prepared from these cells. Coimmunoprecipitation experiments show that these and sphingolipids are part of the same domain. Cross-linking experiments with a photoactivable, radioactive GD1b derivative show that c-Src and Lyn, which are anchored to the membrane via a myristoyl chain, associate directly with GD1b. Csk, which is not inserted in the hydrophobic core of the membrane, is not photolabeled by this ganglioside. These results suggest that lipid-lipid, lipid-protein, and protein-protein interactions cooperate to maintain domain structure. We hypothesize that such interactions might play a role in the process of neuronal differentiation.
authors.affiliation: Department of Medical Chemistry and Biochemistry - LITA - Segrate, The Medical School, University of Milan, Milano, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Prinetti
authors.forename: N
authors.initials: N
authors.lastname: Marano
authors.forename: S
authors.initials: S
authors.lastname: Prioni
authors.forename: V
authors.initials: V
authors.lastname: Chigorno
authors.forename: L
authors.initials: L
authors.lastname: Mauri
authors.forename: R
authors.initials: R
authors.lastname: Casellato
authors.forename: G
authors.initials: G
authors.lastname: Tettamanti
authors.forename: S
authors.initials: S
authors.lastname: Sonnino
mesh_terms: D000818:Animals; D000081247:CSK Tyrosine-Protein Kinase; D002240:Carbohydrate Sequence; D002454:Cell Differentiation; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000378:metabolism*; D005732:Gangliosides; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D011233:Precipitin Tests; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013107:Sphingolipids / Q000378:metabolism*; D019061:src-Family Kinases / Q000378:metabolism*
chemical_list: D005732:Gangliosides; D008565:Membrane Proteins; D013107:Sphingolipids; C033851:ganglioside, GD1b; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; C060902:lyn protein-tyrosine kinase; D019061:src-Family Kinases