Wąhalska Magda, Riepe Celeste, Ślusarz Magdalena J, Graul Małgorzata, Borowski Lukasz S, Qiao Wenjie, Foltynska Michalina, Carette Jan E, Bieńkowska-Szewczyk Krystyna, Szczesny Roman J, Kopito Ron R, Lipińska Andrea D
Laboratory of Virus Molecular Biology, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, 80-307 Gdańsk, Poland.
Department of Biology, Stanford University, Stanford, CA 94305, USA.
bioRxiv. 2023 Sep 27:2023.09.27.559663. doi: 10.1101/2023.09.27.559663.
The transporter associated with antigen processing (TAP) is a key player in the MHC class I-restricted antigen presentation and an attractive target for immune evasion by viruses. Bovine herpesvirus 1 (BoHV-1) impairs TAP-dependent antigenic peptide transport through a two-pronged mechanism in which binding of the UL49.5 gene product to TAP both inhibits peptide transport and promotes its proteasomal degradation. How UL49.5 promotes TAP degradation is unknown. Here, we use high-content siRNA and genome-wide CRISPR-Cas9 screening to identify CLR2 as the E3 ligase responsible for UL49.5-triggered TAP disposal in human cells. We propose that the C-terminus of UL49.5 mimics a C-end rule degron that recruits the E3 to TAP and engages the CRL2 E3 in ER-associated degradation.
与抗原加工相关的转运体（TAP）是MHC I类限制性抗原呈递中的关键参与者，也是病毒免疫逃逸的一个有吸引力的靶点。牛疱疹病毒1型（BoHV-1）通过双管齐下的机制损害TAP依赖性抗原肽转运，其中UL49.5基因产物与TAP的结合既抑制肽转运又促进其蛋白酶体降解。UL49.5如何促进TAP降解尚不清楚。在这里，我们使用高内涵siRNA和全基因组CRISPR-Cas9筛选来确定CLR2是负责在人类细胞中由UL49.5触发的TAP清除的E3连接酶。我们提出，UL49.5的C末端模拟了一个C端规则降解子，该降解子将E3招募到TAP，并使CRL2 E3参与内质网相关降解。
