TY - JOUR
T1 - Palmitoylation of a G protein αi subunit requires membrane localization not myristoylation
AU - Degtyarev, Michael Y.
AU - Spiegel, Allen M.
AU - Jones, Teresa L.Z.
N1 - Copyright:
Copyright 2004 Elsevier B.V., All rights reserved.
PY - 1994/12/9
Y1 - 1994/12/9
N2 - Palmitoylation is a dynamic, post-translational modification of the amino terminus of heterotrimeric G protein α subunits. Since myristoylation, βγ interactions, and membrane attachment also involve the amino terminus of the G protein αil subunit, we studied the relationships between palmitoylation and these events. Using COS cell transfection, the turnover of palmitate was slower on αil subunits co-expressed with β and γ subunits than on the αil subunit expressed alone. Mutation of cysteine 3 of αil prevented [3H]palmitate but not [3H]myristate incorporation and decreased the membrane localization of this protein. This nonpalmitoylated mutant could form a heterotrimer with co-expressed βγ subunits which restored its membrane localization. A nonmyristoylated αil mutant (glycine 2 to alanine) could incorporate [3H]palmitate when co-expressed with βγ subunits and localized to the membrane. The [3H]palmitate turnover of this nonmyristoylated mutant was more rapid than seen with the wild-type αil subunit. While myristoylation is not required for palmitoylation, both myristoylation and βγ association can slow the turnover of palmitate on αil. These results suggest that palmitoylation maintains the membrane attachment of the free α subunit and changes in βγ association could modulate palmitoylation during signaling.
AB - Palmitoylation is a dynamic, post-translational modification of the amino terminus of heterotrimeric G protein α subunits. Since myristoylation, βγ interactions, and membrane attachment also involve the amino terminus of the G protein αil subunit, we studied the relationships between palmitoylation and these events. Using COS cell transfection, the turnover of palmitate was slower on αil subunits co-expressed with β and γ subunits than on the αil subunit expressed alone. Mutation of cysteine 3 of αil prevented [3H]palmitate but not [3H]myristate incorporation and decreased the membrane localization of this protein. This nonpalmitoylated mutant could form a heterotrimer with co-expressed βγ subunits which restored its membrane localization. A nonmyristoylated αil mutant (glycine 2 to alanine) could incorporate [3H]palmitate when co-expressed with βγ subunits and localized to the membrane. The [3H]palmitate turnover of this nonmyristoylated mutant was more rapid than seen with the wild-type αil subunit. While myristoylation is not required for palmitoylation, both myristoylation and βγ association can slow the turnover of palmitate on αil. These results suggest that palmitoylation maintains the membrane attachment of the free α subunit and changes in βγ association could modulate palmitoylation during signaling.
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M3 - Article
C2 - 7983022
AN - SCOPUS:0028075456
SN - 0021-9258
VL - 269
SP - 30898
EP - 30903
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 49
ER -