[대학원 생명과학과 세미나 안내]
연사 : 양성욱 교수(연세대학교 시스템 생물학과)
연제 : Light signaling, proteolysis, and miRNA biogenesis
일시 : 2021년 11월 26일 (금) 오후 5시
장소 : 온라인 화상 강의로 진행됩니다.
초청교수 : 김옥매 교수
Abstract
The core plant microprocessor consists of DICER-LIKE 1 (DCL1), SERRATE (SE), and HYPONASTIC LEAVES 1 (HYL1) and plays a pivotal role in miRNA biogenesis. However, the proteolytic regulation of each component remains elusive. Here, we show that HYL1-CLEAVAGE SUBTILASE 1 (HCS1) is a cytoplasmic protease for HYL1-destabilization. HCS1 dysregulation affects HYL1 proteolysis, and that disrupts miRNA biogenesis. Consistently, the invincible HYL1K154A mutant disables miRNA biogenesis, regardless of its ability for RNA biding and SE and DCL1 interactions, demonstrating the importance of HCS1-mediated HYL1 proteostasis. Moreover, HCS1-activity is regulated by light/dark transition. Under light, cytoplasmic CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) E3 ligase suppresses HCS1-activity. COP1 sterically inhibits HCS1 by obstructing HYL1 access into the catalytic sites of HCS1. In contrast, darkness unshackles HCS1-activity for HYL1-destabilization due to nuclear COP1 relocation. Additionally, autophagy proteolytically tunes HCS1 levels, which positively modulates HYL1-stability. Overall, the COP1-HYL1-HCS1-autophagy network may integrate three essential cellular pathways: the miRNA-biogenetic pathway, light signalling pathway, and autophagy pathway.