TY - JOUR T1 - Signals determining protein tyrosine kinase and glycosyl-phosphatidylinositol-anchored protein targeting to a glycolipid-enriched membrane fraction. JF - Molecular and Cellular Biology JO - Mol. Cell. Biol. SP - 5384 LP - 5391 DO - 10.1128/MCB.14.8.5384 VL - 14 IS - 8 AU - Rodgers, W AU - Crise, B AU - Rose, J K Y1 - 1994/08/01 UR - http://mcb.asm.org/content/14/8/5384.abstract N2 - Glycosyl-phosphatidylinositol (GPI)-anchored membrane proteins and certain protein tyrosine kinases associate with a Triton X-100-insoluble, glycolipid-enriched membrane fraction in MDCK cells. Also, certain protein tyrosine kinases have been shown to associate with GPI-anchored proteins in other cell types. To characterize the interaction between GPI-anchored proteins and protein tyrosine kinases, GPI-anchored proteins were coexpressed with p56lck in HeLa cells. Both proteins were shown to target independently to the glycolipid-enriched membranes. Coimmunoprecipitation of GPI-anchored proteins and p56lck occurred only when both proteins were located in the glycolipid-enriched membranes, and gentle disruption of these membranes abolished the interaction. The GPI anchor was found to be the targeting signal for this membrane fraction in GPI-anchored proteins. Analysis of mutants indicated that p56lck was nearly quantitatively palmitoylated at Cys-5 but not palmitoylated at Cys-3. The nonpalmitoylated cysteine at position 3 was very important for association of p56lck with the membrane fraction, while palmitoylation at Cys-5 promoted only a low level of interaction. Because other src family protein tyrosine kinases that are associated with GPI-anchored proteins always contain a Cys-3, we propose that this residue, in addition to the N-terminal myristate, is part of a common signal targeting these proteins to a membrane domain that has been linked to transmembrane signaling. ER -