Endoplasmic reticulum retention signal

Bichet, D., Cornet, V., Ceib, S., Carlier, E., Volsen, S., Hoshi, T., Mori, Y. and De Waard, M. (2000) The l-ll loop of the Ca2+ channel a, subunit contains an endoplasmic reticulum retention signal antagonized by the beta subunit. Neuron 25, 1 77-190. 

FIGURE 8.1 The carboxy-terminal amino acid residues of carboxylesterase enzymes from disparate species are abgned to show the conserved HXEL motif found among intracellular enzymes (shown in bold letters), and the dismpted versions of this retention motif found in the mouse and rat secreted carboxylesterase isoenzymes (alterations to the motif shown in itahcs). The capacity of the carboxy-terminal HXEL motif to act as an endoplasmic reticulum retention signal has been directly demonstrated. (From Medda and Proia, 1992.)... 

Gabathuler R, Kvist S (1990) The endoplasmic reticulum retention signal of the E3/19K protein of adenovirus type 2 consists of three separate amino acid segments at the carboxv terminus. J Cell Biol 111 1803-1810... 

Figure 46-6. Flow of membrane proteins from the endoplasmic reticulum (ER) to the cell surface. Horizontal arrows denote steps that have been proposed to be signal independent and thus represent bulkflow. The open vertical arrows in the boxes denote retention of proteins that are resident in the membranes of the organelle indicated. The open vertical arrows outside the boxes indicate signal-mediated transport to lysosomes and secretory storage granules. (Reproduced, with permission, from Pfeffer SR, Rothman JE Biosynthetic protein transport and sorting by the endoplasmic reticulum and Golgi. Annu Rev Biochem 1987 56 829.)...

This gene is broadly distributed in skeletal muscle, heart, uterus, and in a variety of non-muscle cells. The mRNA levels are particularly high in intestine, lung and spleen, whereas they are very low in liver, testes, kidney and pancreas. In the muscle tissue SERCA3 may be confined primarily to non-muscle cells (vascular smooth muscle, endothelial cells, etc.). The C-terminus of SERCA3 is Asp-Gly-Lys Lys-Asp-Leu-Lys (Table I) it may serve as a sorting signal for retention of the enzyme in the endoplasmic reticulum [57]. 

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)... 

Ouzzine, M., Magdalou, J., BurcheU, B. and Foumel-Gigleux, S. (1999) An internal signal sequence mediates the targeting and retention of the human UDP-glucuronosyltransferase 1A6 to the endoplasmic reticulum. J. Biol. Chem. 274 31401-31409. 

Pelham. H. R. (1990). The retention signal for soluble proteins of the endoplasmic reticulum. Trends Biochem. Sci. 15, 483-486. 

Intracellular chemokines (or intrakines ) are chemokines where the normal signal peptide that facilitates secretion has been replaced with an endoplasmic reticulum (ER) retention signal (Table III). Thus, intrakines can trap chemokine receptors inside the cells. When delivered by gene-therapy vectors, an SDF-1 intrakine has been shown to reduce cell-surface CXCR4 expression and X4 HIV replication (Chen et al., 1997). A modified RANTES gene is capable of yielding similar results for CCR5. 

Nilsson, T., Jackson, M., and Pederson, P. A. (1989). Short cytoplasmic sequences serve as retention signals for transmembrane proteins in the endoplasmic reticulum. Cell 58, 707-718. 

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