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Updated: Apr 23, 2026

High-Resolution Complexome Profiling by Cryoslicing BN-MS Analysis
Published on: October 15, 2019
Quality control of inner nuclear membrane proteins by the Asi complex
Ombretta Foresti1, Victoria Rodriguez-Vaello1, Charlotta Funaya2
1Cell and Developmental Biology Programme, Centre for Genomic Regulation (CRG), Carrer del doctor Aiguader 88, 08003 Barcelona, Spain. Universitat Pompeu Fabra, Carrer del doctor Aiguader 88, 08003 Barcelona, Spain.
Abstract:
Misfolded proteins in the endoplasmic reticulum (ER) are eliminated by a quality control system called ER-associated protein degradation (ERAD). However, it is unknown how misfolded proteins in the inner nuclear membrane (INM), a specialized ER subdomain, are degraded. We used a quantitative proteomics approach to reveal an ERAD branch required for INM protein quality control in yeast. This branch involved the integral membrane proteins Asi1, Asi2, and Asi3, which assembled into an Asi complex. Besides INM misfolded proteins, the Asi complex promoted the degradation of functional regulators of sterol biosynthesis. Asi-mediated ERAD was required for ER homeostasis, which suggests that spatial segregation of protein quality control systems contributes to ER function.
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