This family contains peptidase family M48 subfamily A-like CaaX prenyl protease 1, most of which are uncharacterized. Some of these contain tetratricopeptide (TPR) repeats at the C-terminus. Proteins in this family contain the zinc metalloprotease motif (HEXXH), likely exposed on the cytoplasmic side. They are thought to be possibly associated with the endoplasmic reticulum (ER), regardless of whether their genes possess the conventional signal motif (KKXX) in the C-terminal. These proteins putatively remove the C-terminal three residues of farnesylated proteins proteolytically.