This family consists of several 24 residue repeats from the Trypanosoma brucei cysteine-rich, acidic integral membrane protein precursor (CRAM). CRAM is concentrated in the flagellar pocket, an invagination of the cell surface of the trypanosome where endocytosis has been documented [1].

1: Characterization of a cDNA encoding a cysteine-rich cell surface protein located in the flagellar pocket of the protozoan Trypanosoma brucei. Lee MG, Bihain BE, Russell DG, Deckelbaum RJ, Van der Ploeg LH; Mol Cell Biol 1990;10:4506-4517. PMID:1697030