Domains that contained dilysine endoplasmic reticulum retrieval signals bound the α -, β ′ -, and ϵ - COP subunits of coatomer, whereas other p24 domains bound the β -, γ -, and ζ - COP subunits and required a phenylalanine - containing motif.
Toxoplasma gondii dense granule protein 3 (GRA3) is a type I transmembrane protein that possesses a cytoplasmic dilysine (KKXX) endoplasmic reticulum (ER) retrieval motif.