Lecture
This lecture covers the regulation of the Endoplasmic Reticulum (ER) chaperone BiP, including its role in protein folding, quality control, and the Unfolded Protein Response (UPR). It explores the impact of high Ca²+ levels on BiP function, the formation of BiP oligomers, and the reversible covalent modification of BiP. The lecture also discusses the interaction between BiP and its substrates, the influence of Ca²+ on BiP's ATPase cycle, and the selective responsiveness of ER-localized Hsp70s to Ca²+. Additionally, it examines how ER Ca²+ depletion affects BiP-substrate interactions and UPR activation. The presentation concludes with alternative models for UPR activation by ER Ca²+ depletion and the implications of Ca²+ on BiP's chaperone cycle.