biostudies-literature00450Li YChina Scholarship CouncilU.S. Department of Health & Human Services | NIH | National Institute of General Medical SciencesWelch FoundationNIGMS NIH HHSNational Science Foundation970-982https://www.ebi.ac.uk/biostudies/studies/S-EPMC7426255biostudies-literatureUnknown6(8)SERRATE (SE) is a key factor in RNA metabolism. Here, we report that SE binds 20S core proteasome α subunit G1 (PAG1) among other components and is accumulated in their mutants. Purified PAG1-containing 20S proteasome degrades recombinant SE via an ATP- and ubiquitin-independent manner in vitro. Nevertheless, PAG1 is a positive regulator for SE in vivo, as pag1 shows comparable molecular and/or developmental defects relative to se. Furthermore, SE is poorly assembled into macromolecular complexes, exemplified by the microprocessor in pag1 compared with Col-0. SE overexpression triggered the destruction of both transgenic and endogenous protein, leading to similar phenotypes of se and SE overexpression lines. We therefore propose that PAG1 degrades the intrinsically disordered portion of SE to secure the functionality of folded SE that is assembled and protected in macromolecular complexes. This study provides insight into how the 20S proteasome regulates RNA metabolism through controlling its key factor in eukaryotes.Nature plantsDegradation of SERRATE via ubiquitin-independent 20S proteasome to survey RNA metabolism.PMC7426255R01 GM127742R01 GM132401MCB-1716243A-1973-201803241R01GM132401Shang BZhou MNagashima YMa ZKoiwa HXie QYan XWang LLi YZhong SZhang XSun DHan JYamaguchi KWang Z45falseDegradation of SERRATE via ubiquitin-independent 20S proteasome to survey RNA metabolism.SERRATE (SE) is a key factor in RNA metabolism. Here, we report that SE binds 20S core proteasome α subunit G1 (PAG1) among other components and is accumulated in their mutants. Purified PAG1-containing 20S proteasome degrades recombinant SE via an ATP- and ubiquitin-independent manner in vitro. Nevertheless, PAG1 is a positive regulator for SE in vivo, as pag1 shows comparable molecular and/or developmental defects relative to se. Furthermore, SE is poorly assembled into macromolecular complexes, exemplified by the microprocessor in pag1 compared with Col-0. SE overexpression triggered the destruction of both transgenic and endogenous protein, leading to similar phenotypes of se and SE overexpression lines. We therefore propose that PAG1 degrades the intrinsically disordered portion of SE to secure the functionality of folded SE that is assembled and protected in macromolecular complexes. This study provides insight into how the 20S proteasome regulates RNA metabolism through controlling its key factor in eukaryotes.2020-01-01T00:00:00Z2020 Aug2024-11-09T10:21:23.086Z2021-02-21T00:37:15ZS-EPMC74262553269089210.1038/s41477-020-0721-4