Elwell Cherilyn A, Czudnochowski Nadine, von Dollen John, Johnson Jeffrey R, Nakagawa Rachel, Mirrashidi Kathleen, Krogan Nevan J, Engel Joanne N, Rosenberg Oren S
Department of Medicine, University of California, San Francisco, San Francisco, United States.
Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States.
Elife. 2017 Mar 2;6:e22709. doi: 10.7554/eLife.22709.
is an obligate intracellular pathogen that resides in a membrane-bound compartment, the inclusion. The bacteria secrete a unique class of proteins, Incs, which insert into the inclusion membrane and modulate the host-bacterium interface. We previously reported that IncE binds specifically to the Sorting Nexin 5 Phox domain (SNX5-PX) and disrupts retromer trafficking. Here, we present the crystal structure of the SNX5-PX:IncE complex, showing IncE bound to a unique and highly conserved hydrophobic groove on SNX5. Mutagenesis of the SNX5-PX:IncE binding surface disrupts a previously unsuspected interaction between SNX5 and the cation-independent mannose-6-phosphate receptor (CI-MPR). Addition of IncE peptide inhibits the interaction of CI-MPR with SNX5. Finally, infection interferes with the SNX5:CI-MPR interaction, suggesting that IncE and CI-MPR are dependent on the same binding surface on SNX5. Our results provide new insights into retromer assembly and underscore the power of using pathogens to discover disease-related cell biology.
是一种专性胞内病原体，存在于膜结合区室即包涵体中。该细菌分泌一类独特的蛋白质，即包涵体蛋白（Incs），其插入包涵体膜并调节宿主 - 细菌界面。我们之前报道过，InceE特异性结合分选连接蛋白5的PX结构域（SNX5 - PX）并破坏retromer转运。在此，我们展示了SNX5 - PX:InceE复合物的晶体结构，显示InceE结合在SNX5上一个独特且高度保守的疏水凹槽上。对SNX5 - PX:InceE结合表面进行诱变会破坏SNX5与阳离子非依赖性甘露糖 - 6 - 磷酸受体（CI - MPR）之间先前未被怀疑的相互作用。添加InceE肽会抑制CI - MPR与SNX5的相互作用。最后，感染会干扰SNX5:CI - MPR相互作用，这表明InceE和CI - MPR依赖于SNX5上的相同结合表面。我们的结果为retromer组装提供了新的见解，并强调了利用病原体发现疾病相关细胞生物学的作用。
