TY - JOUR
T1 - Prenylcysteine analogs mimicking the C-terminus of GTP-binding proteins stimulate exocytosis from permeabilized HIT-T15 cells
T2 - comparison with the effect of Rab3AL peptide
AU - Regazzi, Romano
AU - Sasaki, Takuya
AU - Takahashi, Kazuo
AU - Jonas, Jean Christophe
AU - Volker, Craig
AU - Stock, Jeffry B.
AU - Takai, Yoshimi
AU - Wollheim, Claes B.
N1 - Funding Information:
Supportedb y Grant 32-32376.91fr om the Swiss National ScienceF oundation( C.B.W.) and Grant MV-486 from the AmericanC ancerS ociety( J.B.S.). R.R. is recipient of a Career DevelopmenAtw ard from the Juvenile DiabetesF oundationIn ternationaJl..-C.J. is 'Aspiranto' f the FNRS, Brussels,B elgium.We are indebtedt o Dr. W.E. Balch for providingt he Rab3AL peptide.W e are also gratefutlo Ms. L. Ackermannfo r technicaal ssistance.
PY - 1995/9/21
Y1 - 1995/9/21
N2 - Most guanine nucleotide binding proteins (G-proteins) possess an S-prenylated C-terminal cysteine whose carboxyl group can be reversibly methylated. The prenylcysteine analog N-acetyl-S-geranylgeranyl-cysteine (AGGC) (50 μM), a competitive inhibitor of prenylcysteine methyl transferases, introduced into streptolysin-O permeabilized HIT-T15 cells doubled the rate of basal (0.1 μM Ca2+) and of stimulated (10 μM Ca2+ or 100 μM GTPγS) insulin secretion in a reversible and ATP-dependent manner. N-acetyl-S-farnesyl-cysteine (AFC) was less potent while N-acetyl-S-geranyl-cysteine was inactive. Prenylcysteine action on exocytosis did not involve inhibition of G-protein methylation, since (1) the methyl ester derivative of AFC, an inefficient inhibitor of methyltransferases in HIT-T15 cell fractions, was as potent as AGGC in stimulating exocytosis; (2) S-adenosyl-homocysteine, a general inhibitor of methylation reactions, did not alter basal or GTPγS-triggered secretion while inhibiting Ca2+-induced insulin release. The binding of G-proteins to Rab/GDP-dissociation inhibitor, Rab3A/GTPase activating protein or rabphilin-3A was not affected by the prenylcysteine analogs. AGGC or AFC had the same effect on insulin release as a synthetic peptide mimicking the amino acid residues 52-67 of the G-protein Rab3A (Rab3AL). Moreover, the action on secretion of the combination of Rab3AL and prenylcysteines was not additive. We propose that the prenylcysteines and the Rab3AL peptide influence exocytosis by affecting the association of Rab3A with different proteins of the exocytotic machinery of insulin-secreting cells.
AB - Most guanine nucleotide binding proteins (G-proteins) possess an S-prenylated C-terminal cysteine whose carboxyl group can be reversibly methylated. The prenylcysteine analog N-acetyl-S-geranylgeranyl-cysteine (AGGC) (50 μM), a competitive inhibitor of prenylcysteine methyl transferases, introduced into streptolysin-O permeabilized HIT-T15 cells doubled the rate of basal (0.1 μM Ca2+) and of stimulated (10 μM Ca2+ or 100 μM GTPγS) insulin secretion in a reversible and ATP-dependent manner. N-acetyl-S-farnesyl-cysteine (AFC) was less potent while N-acetyl-S-geranyl-cysteine was inactive. Prenylcysteine action on exocytosis did not involve inhibition of G-protein methylation, since (1) the methyl ester derivative of AFC, an inefficient inhibitor of methyltransferases in HIT-T15 cell fractions, was as potent as AGGC in stimulating exocytosis; (2) S-adenosyl-homocysteine, a general inhibitor of methylation reactions, did not alter basal or GTPγS-triggered secretion while inhibiting Ca2+-induced insulin release. The binding of G-proteins to Rab/GDP-dissociation inhibitor, Rab3A/GTPase activating protein or rabphilin-3A was not affected by the prenylcysteine analogs. AGGC or AFC had the same effect on insulin release as a synthetic peptide mimicking the amino acid residues 52-67 of the G-protein Rab3A (Rab3AL). Moreover, the action on secretion of the combination of Rab3AL and prenylcysteines was not additive. We propose that the prenylcysteines and the Rab3AL peptide influence exocytosis by affecting the association of Rab3A with different proteins of the exocytotic machinery of insulin-secreting cells.
KW - Guanine nucleotide binding protein
KW - HIT-T15 cell
KW - Prenylcysteine
KW - Rab exocyotic effector protein
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U2 - 10.1016/0167-4889(95)00085-7
DO - 10.1016/0167-4889(95)00085-7
M3 - Article
C2 - 7548225
AN - SCOPUS:0029092084
SN - 0167-4889
VL - 1268
SP - 269
EP - 278
JO - BBA - Molecular Cell Research
JF - BBA - Molecular Cell Research
IS - 3
ER -