Just a quick post to report a truly amazing paper published on Science just few days ago. The protein production line in cells involves a quality-control system, associated to the ER, dedicated to the elimination of misfolded proteins, and defined as ER-associated protein degradation (ERAD). The ER holds a specific subdomain in the proximity of the nucleus, the inner nuclear membrane (INM). Scientists at the CRG in Barcelona have found a new quality-control system, associated to and specific of the INM. Quantitative proteomics approach in yeast revealed a new ERAD branch, composed by three proteins forming a complex: the ASI complex. The three proteins, Asi1, Asi-2 and Asi-3 have the function to get rid of misfolded proteins, promote the degradation of functional regulators of sterol biosynthesis and regulate the protein concentration in nucleus. As head investigator and co-author Pedro Carvalho affirms, “(…) this quality control system has two key functions. It gets rid of misfolded proteins and, surprisingly, it also helps prevent the nucleus accumulating proteins that should not be there“. The full article can be found here.