This repeat is found in a wide variety of proteins and generally consists of the motif XYPPX where X can be any amino acid. The family includes annexin VII and the carboxy tail of certain rhodopsins. This family also includes plaque matrix proteins, however this motif is embedded in a ten residue repeat in Mytilus edulis adhesive plaque matrix protein FP1. The molecular function of this repeat is unknown. It is also not clear is all the members of this family share a common evolutionary ancestor due to its short length and biased amino acid composition.