[대학원 생명과학과 세미나 안내]
연사 : 하남출 교수(서울대학교 농생명공학부)
연제 : Structural insights into assembly of intermediate filaments
일시 : 2018년 3월 16일 (금) 오후 5시
장소 : 하나과학관 A동 B131호
초청교수 : 송현규 교수
Abstract
Intermediate filament (IFs) proteins provide vital mechanical support in cells of higher eukaryotes. Nuclear lamins are IF proteins that play a pivotal role in the nuclear envelope structure. A recent cryo-electron tomography (cryo-ET) study revealed that lamins form 3.5 nm-thick filaments. Here, we present a 3.5 nm-thick tetrameric lamin A/C structure with 4 nm-long grooves at both sides. The grooves are extended to the spaces between coils 1a and 2 at both sides of the tetramer, which form two 10 nm-long binding sites for α-helices. These observations suggest a molecular mechanism of lamin filament formation, in which the extended groove in a tetramer interacts longitudinally with coil 2 from another lamin tetramer by a 10 nm overlap termed GC2 interaction. Furthermore, the GC2 interaction, together with an overlapping helical rolling of the so-called ‘precursor form’, explains how the canonical IF, such as vimentin, assemble into a higher order filamentous structure.