InterPro domain: IPR007269

The isoprenylcysteine o-methyltransferase ( 2.1.1.100 ) carries out carboyxl methylation of cleaved eukaryotic proteins that terminate in a CaaX motif. In Saccharomyces cerevisiae, this methylation is carried out by Ste14p, an integral endoplasmic reticulum membrane protein. Ste14p is the founding member of the isoprenylcysteine carboxyl methyltransferase (ICMT) family, whose members share significant sequence homology [ 1 ].

This entry also includes ICMT from Methanosarcina acetivorans ( Q8TMG0 ). It comprises a core of five transmembrane alpha helices and a cofactor-binding pocket enclosed within a highly conserved C-terminal catalytic subdomain [ 2 ].

1. Topological and mutational analysis of Saccharomyces cerevisiae Ste14p, founding member of the isoprenylcysteine carboxyl methyltransferase family. Mol. Biol. Cell 12, 1957-71
2. Mechanism of isoprenylcysteine carboxyl methylation from the crystal structure of the integral membrane methyltransferase ICMT. Mol. Cell 44, 997-1004