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Merck
  • MARCH6 and TRC8 facilitate the quality control of cytosolic and tail-anchored proteins.

MARCH6 and TRC8 facilitate the quality control of cytosolic and tail-anchored proteins.

EMBO reports (2018-03-10)
Sandra Stefanovic-Barrett, Anna S Dickson, Stephen P Burr, James C Williamson, Ian T Lobb, Dick Jh van den Boomen, Paul J Lehner, James A Nathan
摘要

Misfolded or damaged proteins are typically targeted for destruction by proteasome-mediated degradation, but the mammalian ubiquitin machinery involved is incompletely understood. Here, using forward genetic screens in human cells, we find that the proteasome-mediated degradation of the soluble misfolded reporter, mCherry-CL1, involves two ER-resident E3 ligases, MARCH6 and TRC8. mCherry-CL1 degradation is routed via the ER membrane and dependent on the hydrophobicity of the substrate, with complete stabilisation only observed in double knockout MARCH6/TRC8 cells. To identify a more physiological correlate, we used quantitative mass spectrometry and found that TRC8 and MARCH6 depletion altered the turnover of the tail-anchored protein heme oxygenase-1 (HO-1). These E3 ligases associate with the intramembrane cleaving signal peptide peptidase (SPP) and facilitate the degradation of HO-1 following intramembrane proteolysis. Our results highlight how ER-resident ligases may target the same substrates, but work independently of each other, to optimise the protein quality control of selected soluble and tail-anchored proteins.

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Sigma-Aldrich
单克隆抗 β-肌动蛋白抗体 小鼠抗, clone AC-74, purified immunoglobulin, buffered aqueous solution
Sigma-Aldrich
RPMI-1640 培养基, Modified, with sodium bicarbonate, without methionine, cystine and L-glutamine, liquid, sterile-filtered, suitable for cell culture