Abstract
We have identified the palmitoylated cysteine residues of αq and αs, α subunits of two heterotrimeric G proteins. Mutational substitutions of serines for cysteines 9 and 10 in αq and cysteine 3 in αs profoundly alter behavior of the subunits expressed in HEK293 cells. Neither mutant α subunit incorporates palmitate; both mutant proteins are found in the soluble rather than the particulate fraction; mutant αq or αs cannot couple a co-expressed receptor to stimulation of phospholipase C or adenylylcyclase, respectively; cysteine substitution prevents a mutationally activated αq (R183C) from stimulating phospholipase C directly, and reduces but does not abolish the ability of a similarly activated αs (R201C) to stimulate cAMP synthesis. Substitution of a myristoylation sequence for the palmitoylation sites leads to labeling of αq and αs by myristate, rather than by palmitate. Myristoylation restores the abilities of both nonpalmitoylated αq and αs to attach to membranes and, in the case of αq, restores its ability to stimulate phospholipase C, whether triggered by the R183C mutation or by receptor activation. These findings identify palmitoylation as a critical determinant of membrane attachment for αq and αs and show that this modification is required for normal signaling by these proteins.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 25001-25008 |
| Number of pages | 8 |
| Journal | Journal of Biological Chemistry |
| Volume | 268 |
| Issue number | 33 |
| State | Published - Nov 25 1993 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Palmitoylation is required for signaling functions and membrane attachment of Gqα and Gsα. / Wedegaertner, Philip B.; Chu, David H.; Wilson, Paul T.; Levis, Mark J; Bourne, Henry R.
In: Journal of Biological Chemistry, Vol. 268, No. 33, 25.11.1993, p. 25001-25008.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Palmitoylation is required for signaling functions and membrane attachment of Gqα and Gsα
AU - Wedegaertner, Philip B.
AU - Chu, David H.
AU - Wilson, Paul T.
AU - Levis, Mark J
AU - Bourne, Henry R.
PY - 1993/11/25
Y1 - 1993/11/25
N2 - We have identified the palmitoylated cysteine residues of αq and αs, α subunits of two heterotrimeric G proteins. Mutational substitutions of serines for cysteines 9 and 10 in αq and cysteine 3 in αs profoundly alter behavior of the subunits expressed in HEK293 cells. Neither mutant α subunit incorporates palmitate; both mutant proteins are found in the soluble rather than the particulate fraction; mutant αq or αs cannot couple a co-expressed receptor to stimulation of phospholipase C or adenylylcyclase, respectively; cysteine substitution prevents a mutationally activated αq (R183C) from stimulating phospholipase C directly, and reduces but does not abolish the ability of a similarly activated αs (R201C) to stimulate cAMP synthesis. Substitution of a myristoylation sequence for the palmitoylation sites leads to labeling of αq and αs by myristate, rather than by palmitate. Myristoylation restores the abilities of both nonpalmitoylated αq and αs to attach to membranes and, in the case of αq, restores its ability to stimulate phospholipase C, whether triggered by the R183C mutation or by receptor activation. These findings identify palmitoylation as a critical determinant of membrane attachment for αq and αs and show that this modification is required for normal signaling by these proteins.
AB - We have identified the palmitoylated cysteine residues of αq and αs, α subunits of two heterotrimeric G proteins. Mutational substitutions of serines for cysteines 9 and 10 in αq and cysteine 3 in αs profoundly alter behavior of the subunits expressed in HEK293 cells. Neither mutant α subunit incorporates palmitate; both mutant proteins are found in the soluble rather than the particulate fraction; mutant αq or αs cannot couple a co-expressed receptor to stimulation of phospholipase C or adenylylcyclase, respectively; cysteine substitution prevents a mutationally activated αq (R183C) from stimulating phospholipase C directly, and reduces but does not abolish the ability of a similarly activated αs (R201C) to stimulate cAMP synthesis. Substitution of a myristoylation sequence for the palmitoylation sites leads to labeling of αq and αs by myristate, rather than by palmitate. Myristoylation restores the abilities of both nonpalmitoylated αq and αs to attach to membranes and, in the case of αq, restores its ability to stimulate phospholipase C, whether triggered by the R183C mutation or by receptor activation. These findings identify palmitoylation as a critical determinant of membrane attachment for αq and αs and show that this modification is required for normal signaling by these proteins.
UR - http://www.scopus.com/inward/record.url?scp=0027490954&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0027490954&partnerID=8YFLogxK
M3 - Article
C2 - 8227063
AN - SCOPUS:0027490954
VL - 268
SP - 25001
EP - 25008
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 33
ER -