Cytoplasmic retention signals

Pines J, Hunter T. 1994. The differential localization of human cyclins A and B is due to a cytoplasmic retention signal in cyclin B. EMBO J 13 3772-3781. 

Because proteins are synthesized within the cytosol (including on the surface of the ER), it is plausible to postulate that the localization at the cytosol is a default. Such a notion is challenged by the discoveries of several cytoplasmic targeting/retention signals. In one example, the N-terminal 42 residue segment of cyclin B directs it to the cytosol if it is deleted, it is transported to the nucleus and the addition of the segment to cyclin A causes its cytosolic retention (Pines and Hunter,... 

Kanno, Y., Suzuki, M., Nakahama, T., and Inouye, Y. (2005) Characterization of nuclear localization signals and cytoplasmic retention region in the nuclear receptor CAR. Biochim. Biophys. Acta 1745, 215-222. 

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. 

In addition to the membrane-inserted core domain of Kv channels, their cytoplasmic domains have important roles for Kv-channel function [5]. Many of these functions are related to subunits assembly, channel trafficking to and from the plasma membrane, and interactions with cytoskeletal components (Fig. la). A tetramerization (T) domain for subunit assembly has been well defined in Shaker-channels, where it is localized in the amino-terminus. Other Kv-channels (e.g., eag, HERG, KvLQTl) may have comparable domains within the cytoplasmic carboxy-terminus. ER retention and retrieval signals have been found... 

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