The endoplasmic reticulum is part of a protein sorting pathway, or in essence, the transportation system of the eukaryotic cell. The majority of endoplasmic reticulum resident proteins are retained in the endoplasmic reticulum through a retention motif. This motif is composed of four aa at the C-terminal end of the protein sequence. The most common retention sequence is KDEL (lys-asp-glu-leu). Grp78 and Grp94 and PDI all share the C-terminal KDEL sequence. The presence of carboxy-terminal KDEL appears to be necessary for ER retention and appears to be sufficient to reduce the secretion of proteins from the ER.
Intended for research use only. Not for use in human, therapeutic, or diagnostic applications.