Posttranslational modification of the Ha-ras oncogene protein: evidence for a third class of protein carboxyl methyltransferases.

Clarke, Steven; Vogel, Joseph P.; Deschenes, Robert J.; Stock, Jeffry B.

doi:10.1073/pnas.85.13.4643

Cited by 360 publications

(216 citation statements)

References 35 publications

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“…Ras is constitutively carboxyl methylated (22) and expressed at the plasma membrane (23), a localization required for its biological activity (24). Like all CAAX proteins, Ras lacks a signal peptide, is synthesized in the cytosol, and modified immediately posttranslationally by a cytosolic prenyltransferase (25).…”

Section: Fig 3 Complementation Of S Cerevisiae Ste14 Strains Of Smentioning

confidence: 99%

Mammalian Prenylcysteine Carboxyl Methyltransferase Is in the Endoplasmic Reticulum

Dai¹,

Choy²,

Chiu³

et al. 1998

Journal of Biological Chemistry

271

242

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Prenylcysteine carboxyl methyltransferase (pcCMT) is the third of three enzymes that posttranslationally modify C-terminal CAAX motifs and thereby target CAAX proteins to the plasma membrane. Here we report the molecular characterization and subcellular localization of the first mammalian (human myeloid) pcCMT. The deduced amino acid sequence of mammalian pc-CMT predicts a multiple membrane-spanning protein with homologies to the yeast pcCMT, STE14, and the mammalian band 3 anion transporter. The human gene complemented a ste14 mutant. pcCMT mRNAs were ubiquitously expressed in human tissues. An anti-pc-CMT antiserum detected a 33-kDa protein in myeloid cell membranes. Ectopically expressed recombinant pc-CMT had enzymatic activity identical to that observed in neutrophil membranes. Mammalian pcCMT was not expressed at the plasma membrane but rather restricted to the endoplasmic reticulum. Thus, the final enzyme in the sequence that modifies CAAX motifs is located in membranes topologically removed from the CAAX protein target membrane.A number of signaling molecules, including Ras and G proteins, are targeted to the inner leaflet of the plasma membrane by a sequence of posttranslational modifications of a C-terminal CAAX 1 motif that include prenylation, proteolysis, and carboxyl methylation (1). In some cases palmitoylation of an upstream cysteine is also required (2). These modifications render otherwise hydrophilic proteins hydrophobic, promoting association with membranes. The relative contributions of prenylation, proteolysis, and carboxyl methylation to membrane targeting are not well understood. Whereas neutralization of the negative charge on the ␣-carboxyl group by methyl esterification adds to overall hydrophobicity, particularly for farnesylated proteins, this modification contributes little to the affinity of geranylgeranylated proteins for membranes (3). Although processed CAAX proteins can associate with phospholipid vesicles in vitro (4), it is not known whether membrane proteins participate in prenylcysteine membrane association in vivo. The Saccharomyces cerevisiae mating pheromone, a-factor, is a CAAX-processed polypeptide, and both its secretion via the Ste6p transporter (5) and its engagement of the Ste3p G protein-linked receptor (6) are dependent on prenylcysteine carboxyl methylation, suggesting a role for this modification in protein-protein interactions. A cycle of prenylcysteine carboxyl methylation is associated with neutrophil activation (7), and inhibitors of this enzyme block signal transduction in neutrophils (7), macrophages (8), and platelets (9), suggesting that, like bacterial chemotaxis (10), some eukaryotic processes may be regulated by reversible carboxyl methylation.Because prenylcysteine carboxyl methylation cannot be abolished by mutation of the substrate without also eliminating prenylation, elucidation of the role of carboxyl methylation will require characterization and disruption of the methyltransferase. Until recently, the only prenylcysteine carboxyl methyltransfe...

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Section: Fig 3 Complementation Of S Cerevisiae Ste14 Strains Of Smentioning

confidence: 99%

Mammalian Prenylcysteine Carboxyl Methyltransferase Is in the Endoplasmic Reticulum

Dai¹,

Choy²,

Chiu³

et al. 1998

Journal of Biological Chemistry

271

242

View full text Add to dashboard Cite

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“…The motif undergoes a triplet of closely coupled post-translational modifications. Firstly, a prenoid derivative is linked as a thioether to the cysteine residue Casey et al, 1989); second, the -AAX amino acids are removed by proteolysis (Gutierrez et al, 1989) and third, the a-carboxyl group of the now C-terminal cysteine residue is methyl-esterified (Clarke et al, 1988;Gutierrez et al, 1989). We have shown recently that all three of these post-translational processing events at the CAAX motif are required for efficient membrane binding of p21K-ras(B) .…”

Section: Introductionmentioning

confidence: 99%

A CAAX or a CAAL motif and a second signal are sufficient for plasma membrane targeting of ras proteins

Hancock¹,

Cadwaller²,

Paterson³

et al. 1992

Trends in Cell Biology

158

210

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“…Both B-type lamins and prelamin A (the precursor of lamin A) terminate with a CaaX motif, which triggers three posttranslational modifications (3)(4)(5): farnesylation of the carboxyl-terminal cysteine (the "C" in the CaaX motif) (6), endoproteolytic cleavage of the last three amino acids (the -aaX) (7,8), and carboxyl methylation of the newly exposed farnesylcysteine (9,10). Prelamin A undergoes a second endoproteolytic cleavage event, mediated by zinc metalloproteinase STE24 (ZMPSTE24), which removes 15 additional amino acids from the carboxyl terminus, including the farnesylcysteine methyl ester (11)(12)(13)(14).…”

mentioning

confidence: 99%

Farnesylation of lamin B1 is important for retention of nuclear chromatin during neuronal migration

Jung¹,

Nobumori²,

Goulbourne³

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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The role of protein farnesylation in lamin A biogenesis and the pathogenesis of progeria has been studied in considerable detail, but the importance of farnesylation for the B-type lamins, lamin B1 and lamin B2, has received little attention. Lamins B1 and B2 are expressed in nearly every cell type from the earliest stages of development, and they have been implicated in a variety of functions within the cell nucleus. To assess the importance of protein farnesylation for B-type lamins, we created knock-in mice expressing nonfarnesylated versions of lamin B1 and lamin B2. Mice expressing nonfarnesylated lamin B2 developed normally and were free of disease. In contrast, mice expressing nonfarnesylated lamin B1 died soon after birth, with severe neurodevelopmental defects and striking nuclear abnormalities in neurons. The nuclear lamina in migrating neurons was pulled away from the chromatin so that the chromatin was left "naked" (free from the nuclear lamina). Thus, farnesylation of lamin B1-but not lamin B2-is crucial for brain development and for retaining chromatin within the bounds of the nuclear lamina during neuronal migration.genetically modified mouse models T he nuclear lamina is an intermediate filament meshwork that lies beneath the inner nuclear membrane. This lamina provides structural support for the nucleus and also interacts with nuclear proteins and chromatin, thereby affecting many functions within the cell nucleus (1, 2). In mammals, the main protein components of the nuclear lamina are lamins A and C (A-type lamins) and lamins B1 and B2 (B-type lamins).Both B-type lamins and prelamin A (the precursor of lamin A) terminate with a CaaX motif, which triggers three posttranslational modifications (3-5): farnesylation of the carboxyl-terminal cysteine (the "C" in the CaaX motif) (6), endoproteolytic cleavage of the last three amino acids (the -aaX) (7,8), and carboxyl methylation of the newly exposed farnesylcysteine (9, 10). Prelamin A undergoes a second endoproteolytic cleavage event, mediated by zinc metalloproteinase STE24 (ZMPSTE24), which removes 15 additional amino acids from the carboxyl terminus, including the farnesylcysteine methyl ester (11)(12)(13)(14). Lamins B1 and B2 do not undergo the second cleavage step and therefore retain their farnesyl lipid anchor.The discovery that Hutchinson-Gilford progeria syndrome (HGPS) is caused by a LMNA mutation yielding an internally truncated farnesyl-prelamin A (15) has focused interest in the farnesylation of nuclear lamins. This interest has been fueled by the finding that disease phenotypes in mouse models of HGPS could be ameliorated by blocking protein farnesylation with a protein farnesyltransferase inhibitor (FTI) (16)(17)(18)(19). Most recently, children with HGPS seemed to show a positive response to FTI treatment (20).The prospect of using an FTI to treat children with HGPS naturally raises the issue of the importance of protein farnesylation for lamin B1 and lamin B2. The B-type lamins are expressed in all mammalian cells and have been h...

show abstract

Posttranslational modification of the Ha-ras oncogene protein: evidence for a third class of protein carboxyl methyltransferases.

Cited by 360 publications

References 35 publications

Mammalian Prenylcysteine Carboxyl Methyltransferase Is in the Endoplasmic Reticulum

Mammalian Prenylcysteine Carboxyl Methyltransferase Is in the Endoplasmic Reticulum

A CAAX or a CAAL motif and a second signal are sufficient for plasma membrane targeting of ras proteins

Farnesylation of lamin B1 is important for retention of nuclear chromatin during neuronal migration

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