KDEL receptor

Interaction of the KDEL-receptor with soluble luminal... 

This sequence specifies that such proteins will be attached to the inner aspect of the ER in a relatively loose manner. The chaperone BiP (see below) is one such protein. Actually, KDEL-containing proteins first travel to the Golgi, interact there with a specific KDEL receptor protein, and then return in transport vesicles to the ER, where they dissociate from the receptor. 

The retrieval mechanism for the M6P receptor resembles the one previously described for the H/KDEL receptor [53]. Optimal binding of M6P receptor to M6P occurs at pH 6.5-6.7, the pH found in the TGN. When transport vesicles arrive at late endosomes, the pH is lowered by the action of H+ pumps. The affinity of the M6P receptor for its ligands is reduced at acid pHs, resulting in M6P receptor releasing the M6P in the late endosome. As a result, transport of lysosomal hydrolases occurs unidirectionally. Once the M6P receptor releases M6P-bearing hydrolases, the receptor can be returned to the TGN for reuse. Transport of the M6P receptor to either TGN or late endosome relies on signal peptides on the cytoplasmic tail region of the M6P receptor. 

PDI contains a C-terminal tetrapeptide sequence known as the endoplasmic retention signal, KDEL. This anchor mediates the interaction between plasma membrane and membranes of the Golgi apparatus via a KDEL receptor. The PDI KDEL receptor complex is recycled back into the endoplasmic reticulum (Xiao et al., 1999). It is thought that a saturation of the retention mechanism results in the secretion of PDI which is deposited on the cell membrane and stabilized by electrostatic interactions (Terada et al, 1995). The secreted PDI is termed cell surface PDI (csPDI)... 

Kreitman, R. J. and Pastan, I. (1995) Importance of the glutamate residue of KDEL in increasing the cytotoxicity of Pseudomonas exotoxin derivatives and for increased binding to the KDEL receptor. Biochem. J. 307, 29-37. 

Lys-Asp-Glu-Leu (KDEL) ER-resident luminal proteins KDEL receptor in cis-Golgi membrane COPI... 

A FIGURE 17-16 Role of the KDEL receptor in retrieval of ER-resident luminal proteins from the Golgi. 

It has been shown that several proteins of the ER lumen have the common carboxy-terminal sequence KDEL-COOH, and the structural motif is essential for retention of the protein in the luminal site of the ER through KDEL receptor bound to the ER membrane (Pelham, 1990 Tang and Kalow, 1995). 

Kor a and Ozols (1988) and Ozols (1989) established the primary structures of two microsomal esterases purified from rabbit liver and designated them as 60-kDa esterase form 1 and form 2. These two forms of CarbE have the consensus sequence of the ER retention tetra-peptide (HTEL or HIEL in the one-letter code) which recognized with the luminal side of the KDEL receptor, Robbi el al (1990) reported cDNA cloning of rat liver pi 6.1 esterase (ES-10) and pi 5.5 esterase (ES-3, egasyn). This was the... 

Klepsch MM, Persson JO, de Gier JW (2011) Consequences of the overexpression of a eukaryotic membrane protein, the human KDEL receptor, in Escherichia coli. J Mol Biol 407 532-542... 

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