InterPro domain: IPR003675

This family (also known as the ABI (abortive infection) family) contains putative IMPs and has homologues in all three domains of life, including Rce1 from S. cerevisiae [ 1 ]. Rce1 is a type II CAAX prenyl protease that processes all farnesylated and geranylgeranylated CAAX proteins. It is an integral membrane endoprotease localized to the endoplasmic reticulum that mediates the cleavage of the carboxyl-terminal three amino acids from CaaX proteins. It is involved in processing the Ras family of small GTPases, the gamma-subunit of heterotrimeric GTPases, nuclear lamins, and protein kinases and phosphatases [ 2 ]. Three residues of S. cerevisiae Rce1 -E156, H194 and H248- are critical for catalysis [ 3 ]. The structure of Rce1 from the archaea Methanococcus (MmRce1) suggests that this group of proteins represents a novel IMP (intramembrane protease) family, the glutamate IMPs [ 4 ].

1. The abi proteins and their involvement in bacteriocin self-immunity. J. Bacteriol. 192, 2068-76
2. Rce1: mechanism and inhibition. Crit. Rev. Biochem. Mol. Biol. 53, 157-174
3. Mutational analysis of the ras converting enzyme reveals a requirement for glutamate and histidine residues. J. Biol. Chem. 281, 4596-605
4. Mechanism of farnesylated CAAX protein processing by the intramembrane protease Rce1. Nature 504, 301-5