This family of proteins is found in eukaryotes. Proteins in this family are typically between 249 and 341 amino acids in length.

1: Mice expressing aberrant sperm-specific protein PMIS2 produce normal-looking but fertilization-incompetent spermatozoa. Yamaguchi R, Fujihara Y, Ikawa M, Okabe M; Mol Biol Cell. 2012;23:2671-2679. PMID:22621904