[대학원 생명과학과 세미나 안내]
연사 : 이창욱 교수(울산과학기술원)
연제 : Structure and function of membrane contact sites among subcellular compartments
일시 : 2021년 05월 07일 (금) 오후 5시
장소 : 온라인 화상 강의로 진행됩니다.
초청교수 : 지성욱 교수
Abstract
Organelle contact sites are specialized intracellular zones called membrane contact sites (MCS), in which two distinct suborganelles are closely apposed in eukaryotic cells. The MCSs play pivotal roles in cellular processes such as cooperative lipid biosynthesis, ion homeostasis, and interorganellar trafficking of molecules in eukaryotic cells. The MCSs are physically formed through dynamic and direct interactions between proteins that are located in two distinct subcompartments. In this talk, I will introduce structural and functional studies for representative MCS, endoplasmic reticulum (ER)-mitochondria contact site and Nucleus-Vacuole Junction. The endoplasmic reticulum–mitochondria encounter structure (ERMES) is a protein complex that plays a tethering role in physically connecting ER and mitochondria membranes. The ERMES complex is composed of Mdm12, Mmm1, and Mdm34, which have a SMP domain in common, and Mdm10. I will present the crystal structures of Mdm12, Mmm1, and Mdm12-Mmm1 complex. Based on these structures, I will address the molecular mechanisms by which the ERMES complex is organized, mediate the formation of ER-Mitochondrial membrane contact sites, and perform their versatile functions at the circumscribed area. The nucleus–vacuole junction (NVJ) is the first identified interorganellar MCS in the budding yeast, and its formation depends on the nuclear membrane protein Nvj1p and vacuolar membrane protein Vac8p. In this talk, I will show the crystal structure of Vac8p–Nvj1p complex. Based on the structure, I will address a molecular mechanism by which Vac8p facilitates NVJ formation, mediates piecemeal microautophagy of the nucleus, and participates in the cytoplasm-to-vacuole targeting pathway.