This family includes proteins that are mainly from Firmicutes and Proteobacteria. Family members bear the consensus signature of 'EExxR' the second motif 'HxxxE' and the third motif 'H/Qxxxs'. The fourth motif, 'HxxxB', is shared by the PrsW proteases Pfam:PF13367 and the CPBP Pfam:PF02517, and APH-1 families. There are currently no experimental functional data for members of this group, however, they are predicted to be integral membrane proteins with several transmembrane segments and hypothesized metalloprotease function. YhfC intramembrane metalloprotease, CPBP family (type II CAAX Proteases and Bacteriocin Processing enzymes), PrsW proteases and APH-1 are distantly related. They share four predicted core transmembrane segments and possess similar, yet distinct sets of sequence motifs [1].

1: Expansion of type II CAAX proteases reveals evolutionary origin of gamma-secretase subunit APH-1. Pei J, Mitchell DA, Dixon JE, Grishin NV; J Mol Biol. 2011;410:18-26. PMID:21570408