The cytoskeletal protein talin is O-glycosylated.
Talin is a 215-kDa cytoskeletal protein implicated in linking actin filaments to the plasma membrane. We show here that chicken gizzard talin is galactosylated by incubation with UDP-[3H]galactose and galactosyl-transferase. The labeled carbohydrate moiety is removed by beta-elimination and comigrates with Gal beta 1-4GlcNAcitol, indicating that talin belongs to a recently discovered class of cytosolic proteins carrying N-acetylglucosamine (GlcNAc) O-linked to serine or threonine (Holt, G. D., and Hart, G. W. (1986) J. Biol. Chem. 261, 8049-8057). Two glycosylated sequences were identified in the tail domain of talin: ANQAIQMAXQNLVDPAXTQ and GILANQLTNDYGQLAQQ, corresponding to amino acids 1470-1488 and 1883-1899, respectively, of the mouse talin amino acid sequence (Rees, D. J. G., Ades, S. E., Singer, S. J., and Hynes, R. O. (1990) Nature 347, 685-689). The putative glycosylation sites are PAXTQ and QLTND. At most 6% of chicken gizzard talin and 3% of porcine stomach talin are galactosylated by galactosyltransferase. Furthermore, human platelet talin is not labeled at all by the procedure, indicating that it may not be glycosylated.
Hagmann
J
J
Friedrich Miescher Institut, Basel, Switzerland.
Grob
M
M
Burger
M M
MM
D000595:Amino Acid Sequence; D000818:Animals; D001345:Autoradiography; D001792:Blood Platelets / Q000378:metabolism; D002645:Chickens; D005700:Galactosyltransferases / Q000378:metabolism*; D005753:Gastric Mucosa / Q000378:metabolism; D005895:Gizzard, Avian / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009130:Muscle, Smooth / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D013552:Swine; D016608:Talin / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D014316:Tritium; D014531:Uridine Diphosphate Galactose / Q000378:metabolism
D016608:Talin; D014316:Tritium; D014531:Uridine Diphosphate Galactose; D005700:Galactosyltransferases