Disruption of the Mouse Rce1 Gene Results in Defective Ras Processing and Mislocalization of Ras within Cells

doi:10.1074/jbc.274.13.8383

Disruption of the Mouse Rce1 Gene Results in Defective Ras Processing and Mislocalization of Ras within Cells*

From the ^‡Gladstone Institute of Cardiovascular Disease, ^§Cardiovascular Research Institute, Departments of ^¶Medicine and ^§§Pediatrics, University of California, San Francisco, California 94141-9100, ^¶¶Acacia Biosciences, Inc., Richmond, California 94806, and the ^**Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710-3686

Abstract

Little is known about the enzyme(s) required for the endoproteolytic processing of mammalian Ras proteins. We identified a mouse gene (designated Rce1) that shares sequence homology with a yeast gene (RCE1) implicated in the proteolytic processing of Ras2p. To define the role of Rce1in mammalian Ras processing, we generated and analyzedRce1-deficient mice. Rce1 deficiency was lethal late in embryonic development (after embryonic day 15.5). Multiple lines of evidence revealed that Rce1-deficient embryos and cells lacked the ability to endoproteolytically process Ras proteins. First, Ras proteins from Rce1-deficient cells migrated more slowly on SDS-polyacrylamide gels than Ras proteins from wild-type embryos and fibroblasts. Second, metabolic labeling ofRce1-deficient cells revealed that the Ras proteins were not carboxymethylated. Finally, membranes fromRce1-deficient fibroblasts lacked the capacity to proteolytically process farnesylated Ha-Ras, N-Ras, and Ki-Ras or geranylgeranylated Ki-Ras. The processing of two other prenylated proteins, the farnesylated G_γ1 subunit of transducin and geranylgeranylated Rap1B, was also blocked. The absence of endoproteolytic processing and carboxymethylation caused Ras proteins to be mislocalized within cells. These studies indicate thatRce1 is responsible for the endoproteolytic processing of the Ras proteins in mammals and suggest a broad role for this gene in processing other prenylated CAAX proteins.

Footnotes

↵* This work was supported by National Institutes of Health Grants HL-41633, HL-47660, and AG-15451 (to S. G. Y.) and CA-72614 (to K. S.), by American Cancer Society Grant BE 117 (to P. J. C.), and by Acacia Biosciences.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵‖ Supported by a Postdoctoral Fellowship Award for Physicians from the Howard Hughes Medical Institute. To whom correspondence should be addressed: Gladstone Inst. of Cardiovascular Disease, P. O. Box 419100, San Francisco, CA 94141-9100. Tel.: 415-826-7500; Fax: 415-285-5632; E-mail: ekim{at}gladstone.ucsf.edu.
↵‡ Recipient of a Leukemia Society of America postdoctoral fellowship.
Abbreviations:

EST

expressed sequence tag

ES

embryonic stem

kb

kilobase(s)

En

embryonic day n

PBS

phosphate-buffered saline

FTase

farnesyltransferase
- Received December 30, 1998.
The American Society for Biochemistry and Molecular Biology, Inc.