PHYSICS/BK21 SEMINAR [5.14]

본문

Self-Assembly of Filopodia-Like Structures on Supported Lipid Bilayers

* Speaker : Dr. Kwonmoo Lee (Department of Cell Biology, Harvard Medical School)

* Place : Physics Seminar Room (Science Bldg, 3-201)

* Date & Time : May 14 (Fri) 3:00 ~ 4:00 pm

Ø Abstract

Filopodia are finger-like protrusive structures, containing actin bundles. To

probe their mode of assembly we have reconstituted filopodia-like structures

(FLSs) by applying frog egg extracts to supported lipid bilayers containing

phosphatidylinositol(4,5)bisphosphate. FLSs assemble parallel actin bundles

from the membrane with known filopodial components localized to the tip and

shaft. The filopodia tip complexes self-organize and are not templated by

preexisting microdomains in the lipid. The BAR domain protein toca-1 recruits

N-WASP then the Arp2/3 complex and actin assembly follow. Elongation proteins,

Diaphanous-related formin, VASP and fascin are recruited later. Although the

Arp2/3 complex is required for FLS initiation, it is not essential for

elongation, which involves formins. We propose a model for filopodia formation

involving an initial clustering of Arp 2/3 complex regulators,

self-assembly of filopodial tip complexes on the membrane, and outgrowth of parallel actin

bundles.

Contact Person : Prof. Wokyung Sung (054-279-2061, wsung@postech.ac.kr)