Transforming Activity of the Rho Family GTPase, Wrch-1, a Wnt-regulated Cdc42 Homolog, Is Dependent on a Novel Carboxyl-terminal Palmitoylation Motif
| Autor: | Channing J. Der, Adam Shutes, Emily J. Chenette, Carolyn Weinbaum, Janice E. Buss, Audrey Minden, Adrienne D. Cox, Anastacia C. Berzat |
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| Rok vydání: | 2005 |
| Předmět: |
rho GTP-Binding Proteins
Amino Acid Motifs Blotting Western Green Fluorescent Proteins Molecular Sequence Data Palmitic Acid Biotin Endosomes CDC42 GTPase Biology Transfection Biochemistry Mice Cytosol Prenylation Palmitoylation Cell Adhesion Animals Protein palmitoylation Amino Acid Sequence Cysteine cdc42 GTP-Binding Protein Molecular Biology Peptide sequence Cell Proliferation Sequence Homology Amino Acid Cell Membrane Esters Cell Biology Subcellular localization Recombinant Proteins Protein Structure Tertiary Cell biology Microscopy Fluorescence Mutation Mutagenesis Site-Directed NIH 3T3 Cells Protein prenylation Protein Binding Signal Transduction |
| Zdroj: | Journal of Biological Chemistry. 280:33055-33065 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m507362200 |
| Popis: | Wrch-1 is a Rho family GTPase that shares strong sequence and functional similarity with Cdc42. Like Cdc42, Wrch-1 can promote anchorage-independent growth transformation. We determined that activated Wrch-1 also promoted anchorage-dependent growth transformation of NIH 3T3 fibroblasts. Wrch-1 contains a distinct carboxyl-terminal extension not found in Cdc42, suggesting potential differences in subcellular location and function. Consistent with this, we found that Wrch-1 associated extensively with plasma membrane and endosomes, rather than with cytosol and perinuclear membranes like Cdc42. Like Cdc42, Wrch-1 terminates in a CAAX tetrapeptide (where C is cysteine, A is aliphatic amino acid, and X is any amino acid) motif (CCFV), suggesting that Wrch-1 may be prenylated similarly to Cdc42. Most surprisingly, unlike Cdc42, Wrch-1 did not incorporate isoprenoid moieties, and Wrch-1 membrane localization was not altered by inhibitors of protein prenylation. Instead, we showed that Wrch-1 is modified by the fatty acid palmitate, and pharmacologic inhibition of protein palmitoylation caused mislocalization of Wrch-1. Most interestingly, mutation of the second cysteine of the CCFV motif (CCFV > CSFV), but not the first, abrogated both Wrch-1 membrane localization and transformation. These results suggest that Wrch-1 membrane association, subcellular localization, and biological activity are mediated by a novel membrane-targeting mechanism distinct from that of Cdc42 and other isoprenylated Rho family GTPases. |
| Databáze: | OpenAIRE |
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