Role for Ribosome-Associated Complex and Stress-Seventy subfamily B (RAC-Ssb) in integral membrane protein translation [Protein Structure and Folding]

Targeting of most integral membrane proteins to the endoplasmic reticulum is controlled by the signal recognition particle (SRP), which recognizes a hydrophobic signal sequence near the protein N-terminus. Proper folding of these proteins is monitored by the unfolded protein response, and involves protein degradation pathways to ensure quality control. Here, we identify a new pathway for quality control of major facilitator superfamily transporters that occurs before the first transmembrane helix--the signal sequence recognized by SRP--is made by the ribosome. Increased rates of translation elongation of the N-terminal sequence of these integral membrane proteins can divert the nascent protein chains to the ribosome-associated complex (RAC) and Stress-Seventy Subfamily B (Ssb) chaperones. We also show that quality control of integral membrane proteins by RAC-Ssb couples translation rate to the unfolded protein response, which has implications for understanding mechanisms underlying human disease and protein production in biotechnology.

from # All Medicine by Alexandros G. Sfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2wtiY79
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