생명과학과 신임교원 채용 후보 공개세미나

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  • 2017-01-06


생명과학과 신임교원 채용 후보 공개세미나

[Life Sciences Faculty Candidate Seminar Notice]
              ▶Subject: Dual hijack by HIV Vif promotes APOBEC3 ubiquitination and perturbation of RUNX mediated transcription
              ▶Speaker: Dong Young Kim, Ph.D. (Yeungnam University)
              ▶Date: 4:00 PM/Nov. 28(Mon.)/2016
              ▶Place: Auditorium(1F), Postech Biotech Center
 The HIV-1 accessory protein Vif hijacks a cellular Cullin-RING ubiquitin ligase, CRL5, to promote the degradation of the APOBEC3 family of anti-viral factors. Though Vif is an important target for the development of the antiviral drug, the active form has been not purified for last 30 years and thus in vitro study of Vif also has been highly limited. We reveal, using an affinity tag/purification mass spectrometry approach, that Vif additionally recruits the transcription cofactor CBFβ to this ubiquitin ligase complex. And we demonstrate that CBFβ is required for the assembly of a well-ordered CRL5-Vif complex by inhibiting Vif oligomerization and by activating CRL5-Vif via direct interaction. The CRL5-Vif-CBFβ holoenzyme forms a well-defined heterohexamer, indicating that Vif simultaneously hijacks CRL5 and CBFβ. Heterodimers of CBFβ and RUNX transcription factors contribute toward the regulation of diverse genes, including those with immune system functions. We show that binding of Vif to CBFβ is mutually exclusive with RUNX heterodimerization and impacts the expression of genes whose regulatory domains are associated with RUNX1. Our results provide a mechanism by which a pathogen with limited coding capacity uses one factor to hijack multiple host pathways. Additionally, the results suggest a new paradigm for the functional identification and the homogeneous purification of intrinsically unstable virus proteins.