A novel endocytosis signal related to the KKXX ER-retrieval signal.

AUTOR(ES)

Itin, C

RESUMO

Membrane proteins often contain a sorting signal in their cytoplasmic tail that promotes their clustering into coated vesicles at a specific cellular site. ERGIC-53 contains a cytoplasmic ER-retrieval signal, KKFF. However, overexpressed ERGIC-53 is transported to the cell surface and rapidly endocytosed. Here we report that ERGIC-53 carries a previously undescribed endocytosis signal. Surprisingly, the signal was KKFF and like the ER-retrieval signal required a C-terminal position. In fact, the minimal consensus sequence determined by substitutional mutagenesis (K-K/R-F/Y-F/Y) was related to the ER-retrieval consensus (K-K-X-X). Furthermore, we provide evidence that internalization of VIP36, a protein that cycles between plasma membrane and Golgi, is mediated by a signal at its C-terminus that matches the internalization consensus sequence. The relatedness of the two signals suggests that coatomer-mediated retrieval of proteins may be mechanistically more related to clathrin-dependent sorting than previously anticipated.

Documentos Relacionados

• An isoform of the Golgi t-SNARE, syntaxin 5, with an endoplasmic reticulum retrieval signal.
• Ubiquitin as a degradation signal.
• pBD7, a novel cell-free expression vector with efficient translation initiation signal.
• A novel glycoprotein of feline infectious peritonitis coronavirus contains a KDEL-like endoplasmic reticulum retention signal.
• Characterization of the polyomavirus late polyadenylation signal.