unfolded protein Dissociation of ATF6-alpha:BiP Complex ATF6-alpha is a transmembrane protein located in the endoplasmic reticulum (ER) membrane with N-terminal cytoplasmic and C-terminal luminal domains. BiP binds the luminal domain of ATF6-alpha via the substrate binding domain of BiP. Binding of BiP blocks 2 Golgi localization sequences on ATF6-alpha, maintaining ATF6-alpha in the ER. <br> BiP is also a general chaperone capable of binding unfolded proteins in the ER lumen. When chaperone activity in the ER is overwhelmed, BiP dissociates from ATF6-alpha and binds the excess unfolded proteins. It is unclear whether the dissociation is due to competition of unfolded proteins for BiP or to a more specific interaction between BiP and ATF6-alpha. The dissociation exposes the Golgi localization sequences of ATF6-alpha and allows ATF6-alpha to transit to the Golgi. Authored: May, B, 2009-06-02 00:51:49 Edited: May, B, 2009-06-02 00:51:49 Pubmed11821395 Pubmed12110171 Pubmed15657421 Reactome Database ID Release 43381158 Reactome, http://www.reactome.org ReactomeREACT_18323 Reviewed: D'Eustachio, P, Matthews, L, Gillespie, ME, 2008-12-02 16:25:31 Reviewed: Urano, F, 2010-04-30 ATF6-alpha:BiP BiP:Unfolded Protein