Absence of the CAAX Endoprotease Rce1: Effects on Cell Growth and Transformation

Bergö, Martin O.; Ambroziak, Patricia; Gregory, Cria; George, Amanda M.; Otto, James C.; Kim, Edward; Nagase, Hiroki; Casey, Patrick J.; Balmain, Allan; Young, Stephen G.

doi:10.1128/mcb.22.1.171-181.2002

Cited by 137 publications

(131 citation statements)

References 38 publications

(49 reference statements)

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“…To address the importance of postprenylation processing, we examined the properties of specific CAAX proteins in Rce1 Ϫ/Ϫ and Icmt Ϫ/Ϫ MEFs. We have previously found that K-Ras was mislocalized to the cytosol in both Rce1- (Kim et al, 1999;Bergo et al, 2002) and Icmtdeficient (Bergo et al, 2000) cells. In the case of the Rce1-deficient cells, the mislocalization of K-Ras was associated with reduced susceptibility to K-Ras-induced oncogenic transformation (Bergo et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

PostprenylationCAAXProcessing Is Required for Proper Localization of Ras but Not Rho GTPases

Michaelson

Ali

Chiu

et al. 2005

MBoC

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156

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The CAAX motif at the C terminus of most monomeric GTPases is required for membrane targeting because it signals for a series of three posttranslational modifications that include isoprenylation, endoproteolytic release of the C-terminal-AAX amino acids, and carboxyl methylation of the newly exposed isoprenylcysteine. The individual contributions of these modifications to protein trafficking and function are unknown. To address this issue, we performed a series of experiments with mouse embryonic fibroblasts (MEFs) lacking Rce1 (responsible for removal of the -AAX sequence) or Icmt (responsible for carboxyl methylation of the isoprenylcysteine). In MEFs lacking Rce1 or Icmt, farnesylated Ras proteins were mislocalized. In contrast, the intracellular localizations of geranylgeranylated Rho GTPases were not perturbed. Consistent with the latter finding, RhoGDI binding and actin remodeling were normal in Rce1-and Icmtdeficient cells. Swapping geranylgeranylation for farnesylation on Ras proteins or vice versa on Rho proteins reversed the differential sensitivities to Rce1 and Icmt deficiency. These results suggest that postprenylation CAAX processing is required for proper localization of farnesylated Ras but not geranygeranylated Rho proteins.

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Section: Discussionmentioning

confidence: 99%

PostprenylationCAAXProcessing Is Required for Proper Localization of Ras but Not Rho GTPases

Michaelson

Ali

Chiu

et al. 2005

MBoC

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141

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“…Studies of mouse fibroblasts with either null or conditional Rce1 mutant alleles have provided compelling evidence that the membrane association, plasma membrane targeting and transformation capacity of Ras are all substantially lower when Rce1p function is lacking; in fact cells lacking Rce1 function are sensitized to FTI treatment [34][35][36] . These findings have spurred renewed interest in developing Rce1 inhibitors.…”

Section: Enzymatic Processing Of Prenylated Proteinsmentioning

confidence: 99%

Therapeutic intervention based on protein prenylation and associated modifications

et al. 2006

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In eukaryotic cells, a specific set of proteins are modified by C-terminal attachment of 15-carbon farnesyl groups or 20-carbon geranylgeranyl groups that function both as anchors for fixing proteins to membranes and as molecular handles for facilitating binding of these lipidated proteins to other proteins. Additional modification of these prenylated proteins includes C-terminal proteolysis and methylation, and attachment of a 16-carbon palmitoyl group; these modifications augment membrane anchoring and alter the dynamics of movement of proteins between different cellular membrane compartments. The enzymes in the protein prenylation pathway have been isolated and characterized. Blocking protein prenylation is proving to be therapeutically useful for the treatment of certain cancers, infection by protozoan parasites and the rare genetic disease Hutchinson-Gilford progeria syndrome.Isoprenoids are lipids made of five-carbon blocks, and they constitute one of the main classes of natural products. A subset of isoprenoids called prenyl groups are found on a variety of biological substances, including proteins. Prenylated proteins and peptides are found in most (if not all) eukaryotes. They arise from the post-translational attachment of 15-carbon farnesyl or 20-carbon geranylgeranyl groups to the C-terminal segment of proteins. Protein prenyl groups not only are hydrophobic elements that bind proteins to membranes, but, at least in some cases, they also function as molecular handles that bind to hydrophobic grooves on the surface of soluble protein factors; these factors then remove the prenylated protein from the membrane in a regulated manner. NIH Public Access Author ManuscriptNat Chem Biol. Author manuscript; available in PMC 2010 June 28. Published in final edited form as:Nat Chem Biol. 2006 October ; 2(10): 518-528. doi:10.1038/nchembio818. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptProtein prenylation has been vigorously studied over the past ~15 years because it is found on several signaling proteins (including heterotrimeric G proteins) that connect cell surface receptors to intracellular effectors, and also on Ras proteins, one of the most common oncoproteins found in human tumors. Ras proteins serve as molecular switches at cellular membranes to control propagation of growth signals from cell surface receptors to nuclear transcription factors. Because Ras mutations are important in many human cancers, there has been extensive focus on Ras prenylation. Discovery of protein prenyl groups and structural varietiesThe first reports of prenylated proteins and peptides described the secreted pheromone peptides from jelly fungi 1,2 , whose structure resembles that of the well-known a-factor mating pheromone from baker's yeast (Saccharomyces cerevisiae), which contains a cysteine methylester farnesylated at the C terminus 3 . In the 1980s, studies on the timing of cholesterol biosynthesis with respect to the cell cycle in human cells led to the discovery that a compound deriv...

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“…In mammalian cells, Rce1 deficiency eliminated the endoproteolytic processing of the Ras proteins and led to a partial mislocalization of Ras proteins away from the plasma membrane (6,17). However, Rce1 deficiency had only a marginal effect on fibroblast cell growth (17).…”

mentioning

confidence: 99%

“…In yeast, RCE1 deficiency caused a partial mislocalization of Ras2p away from the plasma membrane, but there was no detectable effect on cell growth or vitality (5). In mammalian cells, Rce1 deficiency eliminated the endoproteolytic processing of the Ras proteins and led to a partial mislocalization of Ras proteins away from the plasma membrane (6,17). However, Rce1 deficiency had only a marginal effect on fibroblast cell growth (17).…”

mentioning

confidence: 99%

“…A recent study indicated that Cre-mediated excision of Rce1 in mouse fibroblasts limits Ras-induced transformation of cells (17), but much more research is required to determine if Rce1 would be a useful therapeutic target. In any case, if Rce1 inhibitor drugs were shown to be effective in blocking tumor growth in vivo, it would be essential to document that they could be given safely.…”

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On the Physiological Importance of Endoproteolysis of CAAX Proteins

Bergö

Lieu

Gavino

et al. 2004

Journal of Biological Chemistry

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Proteins terminating with a CAAX motif, such as the Ras proteins and the nuclear lamins, undergo posttranslational modification of a C-terminal cysteine with an isoprenyl lipid via a process called protein prenylation. After prenylation, the last three residues of CAAX proteins are clipped off by Rce1, an integral membrane endoprotease of the endoplasmic reticulum. Prenylation is crucial to the function of many CAAX proteins, but the physiologic significance of endoproteolytic processing has remained obscure. To address this issue, we used Cre/loxP recombination techniques to create mice lacking Rce1 in the heart, an organ where Rce1 is expressed at particularly high levels. The hearts from heart-specific Rce1 knockout mice manifested reduced levels of both the Rce1 mRNA and CAAX endoprotease activity, and the hearts manifested an accumulation of CAAX protein substrates. The heart-specific Rce1 knockout mice initially appeared healthy but died starting at 3-5 months of age. By 10 months of age, ϳ70% of the mice had died. Pathological studies revealed that the heartspecific Rce1 knockout mice had a dilated cardiomyopathy. By contrast, liver-specific Rce1 knockout mice appeared healthy, had normal transaminase levels, and had normal liver histology. These studies indicate that the endoproteolytic processing of CAAX proteins is essential for cardiac function but is less important for the liver.Proteins terminating with a CAAX 1 motif, such as the nuclear lamins and the Ras and Rho proteins, undergo three sequential post-translational processing steps (1-4). First, the C-terminal cysteine (i.e. the C of the CAAX motif) is "lipidated" with a 15-carbon farnesyl or a 20-carbon geranylgeranyl lipid. This processing step is carried out by cytosolic prenyltransferases (protein farnesyltransferase and protein geranylgeranyltransferase type I). Second, a prenylprotein-specific endoprotease of the endoplasmic reticulum, Ras-converting enzyme 1 (Rce1), clips off the last three amino acids from the protein (i.e. the -AAX) (5-7). Third, the newly exposed C-terminal isoprenylcysteine is methylesterified by isoprenylcysteine carboxyl methyltransferase (Icmt), a prenylprotein-specific, S-adenosylmethionine-dependent methyltransferase of the endoplasmic reticulum (8 -11).Prenylation of CAAX proteins is vitally important to eukaryotic cells (1-4). Yeast lacking the shared ␣-chain of farnesyltransferase and geranylgeranyltransferase type I are not viable (12). In mammalian cells, prenylation of CAAX proteins is absolutely required for their proper targeting to membrane surfaces and for proper protein function (1-4). The importance of protein farnesylation is clearly indicated by the fact that mice lacking farnesyltransferase die early during embryonic development (before embryonic day 6.5). 2 The geranylgeranylation of CAAX proteins is also critical for normal cellular function. Drugs that inhibit geranylgeranylation of CAAX proteins have pronounced effects on cell growth and can trigger apoptosis (13-15). Further underscoring the im...

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Absence of the CAAX Endoprotease Rce1: Effects on Cell Growth and Transformation

Cited by 137 publications

References 38 publications

PostprenylationCAAXProcessing Is Required for Proper Localization of Ras but Not Rho GTPases

PostprenylationCAAXProcessing Is Required for Proper Localization of Ras but Not Rho GTPases

Therapeutic intervention based on protein prenylation and associated modifications

On the Physiological Importance of Endoproteolysis of CAAX Proteins

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