[BK21 Plus Seminar]

▶Subject: The molecular basis for subversion of the ubiquitin proteasome pathway by HIV Vpr and Vpx proteins

▶Speaker: Jinwoo Ahn, Ph. D. (Department of Structural Biology, University of Pittsburgh School of Medicine)

▶Date: 4:00PM/July 3(Mon.)/2017

▶Place: Life Science Bldg. #104

▶Abctract
The HIV accessory protein Vpr and Vpx are required for efficient viral infections in immune cells. The biological activities of Vpr and Vpx are closely tied to the interaction with the DCAF1, a substrate receptor of the Cullin4-RING E3 ubiquitin ligase (CLR4), involved in the host proteasome-mediated protein degradation pathway. Specifically, Vpx loads anti-viral restriction factor SAMHD1 onto CRL4-DCAF1, whereas Vpr targets multiple DNA repair proteins including UNG2, MUS81, and HLTF by loading them onto the same E3 ligase. I will describe the structural and molecular basis for subversion of host proteasome degradation machinery by these HIV virulence factors. In particular, Vpr and Vpx utilize similar N-terminal and helical regions to bind DCAF1 and create distinctive binding interfaces for recruitment of their respective cellular targets. These findings reveal that Vpr and Vpx have evolved to target specific targets in different aspects of cellular pathways to facilitate HIV infection.
SAMHD1 is a triphosphohydrolase that limits the pool of dNTPs available for reverse transcription of the viral genome. SAMHD1 has been a recent focus of study since it was identified as a potent human immunodeficiency virus-1 (HIV-1) restriction factor in the intrinsic antiviral immune system. I will describe structural and biochemical basis for allosteric regulation of SAMHD1 by nucleoside triphosphates.

▶Inquiry: Prof. Cheol-Sang Hwang (279-2352)

* This seminar will be given in English.
Please refrain from taking photos during seminars. *