title: RHO methylation matters: a role for isoprenylcysteine carboxylmethyltransferase in cell migration and adhesion.
abstract: Numerous proteins involved in diverse aspects of cell biology undergo a process of post-translational modification termed prenylation. The prenylation pathway consists of three enzymatic steps, the final of which is methylation of the carboxyl-terminal prenylcysteine formed in the first two steps by the enzyme isoprenylcysteine carboxylmethyltransferase (Icmt). Due to the prevalence of prenylated proteins in cancer biology, and the findings that several of the proteins are involved in processes controlling cell migration and adhesion, we sought to examine the role of Icmt - mediated methylation on cell behavior associated with metastasis. We found that inhibition of methylation reduces migration of the highly metastatic MDA-MB-231 breast cancer cell line. In addition, cell adhesion and cell spreading were also impaired by Icmt inhibition. Further investigation revealed that inhibition of Icmt significantly decreased the activation of both RhoA and Rac1, which are both prenylated proteins. The data obtained were consistent with the decreased activation being due to an increase in Rho GDP-dissociation inhibitor (GDI) binding by both proteins in the absence of their methylation. Importantly, the addition of exogenous RhoA or Rac1 to cells in which Icmt was inhibited was able to partially, but selectively, rescue directed and random migration, respectively. These results establish a role for Icmt-mediated methylation in cell migration, and point to specific prenylated proteins involved in this biology. The prenylation pathway has been targeted for oncogenic therapies, but the role of methylation in cell motility had been largely unexplored until now. The finding that methylation of Rho family members impacts on a specific component of their function provides an additional avenue through which to interrogate the biology of this important class of regulatory proteins.
authors.affiliation: Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Ian
authors.initials: I
authors.lastname: Cushman
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Casey
mesh_terms: D002448:Cell Adhesion / Q000502:physiology*; D045744:Cell Line, Tumor / Q000737:chemistry; D002465:Cell Movement / Q000502:physiology*; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000737:chemistry*; D006801:Humans; D008745:Methylation; D011485:Protein Binding; D011496:Protein Methyltransferases / Q000737:chemistry*; D017368:Protein Prenylation / Q000502:physiology; D011499:Protein Processing, Post-Translational / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D020830:rac1 GTP-Binding Protein / Q000737:chemistry; D020741:rho GTP-Binding Proteins / Q000737:chemistry*; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D020742:rhoA GTP-Binding Protein / Q000737:chemistry
chemical_list: D020730:Guanine Nucleotide Dissociation Inhibitors; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D011496:Protein Methyltransferases; C056501:protein-S-isoprenylcysteine O-methyltransferase; D020830:rac1 GTP-Binding Protein; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein
references.citation: Cancer Treat Rev. 2004 Nov;30(7):609-41
references.pmid: 15531395
references.citation: J Biol Chem. 2009 Oct 9;284(41):27964-27973
references.pmid: 19651782
references.citation: Blood. 2008 Aug 15;112(4):1357-65
references.pmid: 18502828
references.citation: Nature. 2002 Dec 12;420(6916):629-35
references.pmid: 12478284
references.citation: J Mol Biol. 2004 Oct 15;343(2):417-33
references.pmid: 15451670
references.citation: Cell. 2000 Feb 4;100(3):345-56
references.pmid: 10676816
references.citation: Oncogene. 1991 Apr;6(4):515-22
references.pmid: 1903193
references.citation: Nat Rev Cancer. 2007 Apr;7(4):295-308
references.pmid: 17384584
references.citation: J Biol Chem. 2005 May 13;280(19):18790-6
references.pmid: 15647276
references.citation: J Biol Chem. 2008 Sep 12;283(37):25150-25163
references.pmid: 18614539
references.citation: Annu Rev Biochem. 1996;65:241-69
references.pmid: 8811180
references.citation: Biochemistry. 2001 Aug 28;40(34):10007-13
references.pmid: 11513578
references.citation: Nat Chem Biol. 2006 Oct;2(10):518-28
references.pmid: 16983387
references.citation: J Clin Invest. 2004 Feb;113(4):513-5
references.pmid: 14966560
references.citation: J Biol Chem. 1997 Dec 26;272(52):33175-80
references.pmid: 9407105
references.citation: Cell Signal. 2000 Aug;12(8):515-24
references.pmid: 11027944
references.citation: Annu Rev Cell Biol. 1994;10:181-205
references.pmid: 7888176
references.citation: J Biol Chem. 1998 Jun 12;273(24):15030-4
references.pmid: 9614111
references.citation: Am J Physiol Lung Cell Mol Physiol. 2004 Dec;287(6):L1091-7
references.pmid: 15286003
references.citation: Proc Natl Acad Sci U S A. 1991 Aug 1;88(15):6442-6
references.pmid: 1907371
references.citation: Curr Opin Investig Drugs. 2002 Sep;3(9):1312-7
references.pmid: 12498006
references.citation: Mol Biol Cell. 2005 Apr;16(4):1606-16
references.pmid: 15659645
references.citation: Science. 1997 Mar 21;275(5307):1796-800
references.pmid: 9065405
references.citation: Circ Res. 2004 Feb 20;94(3):306-15
references.pmid: 14699010
references.citation: J Biol Chem. 1996 Mar 8;271(10):5289-92
references.pmid: 8621375
references.citation: Cancer Metastasis Rev. 2009 Jun;28(1-2):65-76
references.pmid: 19160018
references.citation: Sci STKE. 2004 Sep 07;2004(250):RE13
references.pmid: 15367757
references.citation: Circ Res. 2005 Jun 10;96(11):1152-60
references.pmid: 15890975
references.citation: Proc Natl Acad Sci U S A. 2005 Mar 22;102(12):4336-41
references.pmid: 15784746
references.citation: Curr Med Chem. 2008;15(15):1478-92
references.pmid: 18537624
references.citation: J Biol Chem. 2008 Jul 4;283(27):18678-84
references.pmid: 18434300
references.citation: Oncologist. 2006 Mar;11(3):306-15
references.pmid: 16549815
references.citation: J Clin Invest. 2004 Feb;113(4):539-50
references.pmid: 14966563