The retromer is a protein complex that mediates retrograde transport of transmembrane cargoes from endosomes to the trans-Golgi network （TGN）. It is comprised of a cargo-selection subcomplex of Vps26, Vps29 and Vps3...The retromer is a protein complex that mediates retrograde transport of transmembrane cargoes from endosomes to the trans-Golgi network （TGN）. It is comprised of a cargo-selection subcomplex of Vps26, Vps29 and Vps35 and a membrane-binding coat subcomplex of sorting nexins （SNXs）. Previous studies identified SNX1/2 as one of the components of the SNX subcomplex, and SNX5/6 as candidates for the second SNX. How the retromer-associated cargoes are recognized and transported by molecular motors are largely unknown. In this study, we found that one of SNX1/2＇s dimerization partners, SNX6, interacts with the p150Gued subunit of the dynein/dynactin motor complex. We present evidence that SNX6 is a component of the retromer, and that recruitment of the motor complex to the membrane-associated retromer requires the SNX6-pl50Gued interaction. Disruption of the SNX6-pl50Glued interaction causes failure in formation and detachment of the tubulovesicular sorting structures from endosomes and results in block of CI-MPR retrieval from endosomes to the TGN. These observations indicate that in addition to SNX1/2, SNX6 in association with the dynein/dynactin complex drives the formation and movement of tubular retrograde intermediates.展开更多
Background:Dynactin(DCTN)can activate cytoplasmic dynein and drive intracellular organelle transport containing six family members(DCTN1 to DCTN6).The DCTN family has been studied as cancer-related genes or biomarkers...Background:Dynactin(DCTN)can activate cytoplasmic dynein and drive intracellular organelle transport containing six family members(DCTN1 to DCTN6).The DCTN family has been studied as cancer-related genes or biomarkers in various cancers.Nevertheless,in hepatocellular carcinoma(HCC),the functions and prognostic roles of the DCTN family have been unexplored.Methods:We evaluated the diagnostic and survival effects of DCTN subunits in HCC through bioinformatics analysis and validated the results of bioinformatics by our data to address this problem.Results:The results of bioinformatics analysis found that DCTN2 was a significant prognostic factor in HCC,and high-level DCTN2 can predict poor patient survival in HCC.Cox regression analysis also suggested that DCTN2(hazard ratio=1.748,95%confidence interval 1.190-2.568,P=0.004)is an independent prognostic factor for patient survival.Western blot and quantitative reverse transcriptionpolymerase chain reaction assays confirmed that the protein and mRNA expression levels of DCTN2 were upregulated in HCC cell lines.The proliferation,invasion,and migration were decreased and cell apoptosis was enhanced after DCTN2 was knocked down in Huh7 and Hep3B cells.DCTN2 promoted the cell cycle progression through regulating the expression of cell cycle regulatory proteins cyclindependent kinase 4,Cyclin D1,and p21.Conclusions:We propose that DCTN2 can serve as a prognostic marker for HCC.DCTN2 acts as an oncogene and promotes the cell cycle progression through the G1/S phase-related signaling pathway.展开更多
基金We thank Yingfang Liu （Institute of Biophysics, Chinese Acad- emy of Sciences） for advice on PX domain structure and SNX6 mutations. We are particularly grateful to Yanmin Yang （Stanford University, USA） for insightful discussions and the Flag-MAP1B LC construct. We also thank Juan S Bonifacino （NIH, USA） for the rabbit anti-CI-MPR antibody, Hiroyoshi Ariga （Hokkaido University, Japan） for Flag- and HA-tagged human SNX6 overexpression constructs, and Li Yu （Tsinghua University, China） for the YFP-EEA1 expression construct. We thank Chonglin Yang （Institute of Genetics and Developmental Biology, Chinese Academy of Sciences）, Dahua Chen （Institute of Zoology, Chinese Academy of Sciences） and Li Yu for critical reading of the manuscript. This work was supported by grants from the National Natural Science Foundation of China （30770675） and Chinese Academy of Sciences （KSCX1-YW-R-37）. J-J Liu is supported by the CAS 100-Tal- ents Program.
文摘The retromer is a protein complex that mediates retrograde transport of transmembrane cargoes from endosomes to the trans-Golgi network （TGN）. It is comprised of a cargo-selection subcomplex of Vps26, Vps29 and Vps35 and a membrane-binding coat subcomplex of sorting nexins （SNXs）. Previous studies identified SNX1/2 as one of the components of the SNX subcomplex, and SNX5/6 as candidates for the second SNX. How the retromer-associated cargoes are recognized and transported by molecular motors are largely unknown. In this study, we found that one of SNX1/2＇s dimerization partners, SNX6, interacts with the p150Gued subunit of the dynein/dynactin motor complex. We present evidence that SNX6 is a component of the retromer, and that recruitment of the motor complex to the membrane-associated retromer requires the SNX6-pl50Gued interaction. Disruption of the SNX6-pl50Glued interaction causes failure in formation and detachment of the tubulovesicular sorting structures from endosomes and results in block of CI-MPR retrieval from endosomes to the TGN. These observations indicate that in addition to SNX1/2, SNX6 in association with the dynein/dynactin complex drives the formation and movement of tubular retrograde intermediates.
基金This work was funded by the National Natural Science Foundation of China(No.81702375)the Natural Science Foundation of Guangdong Province of China(No.2021A15150124)+1 种基金the Sun Yatsen university young teacher training program(No.19ykpy32)the Scientific Research Project of Dongguan Binhaiwan Central Hospital(No.2021001).
文摘Background:Dynactin(DCTN)can activate cytoplasmic dynein and drive intracellular organelle transport containing six family members(DCTN1 to DCTN6).The DCTN family has been studied as cancer-related genes or biomarkers in various cancers.Nevertheless,in hepatocellular carcinoma(HCC),the functions and prognostic roles of the DCTN family have been unexplored.Methods:We evaluated the diagnostic and survival effects of DCTN subunits in HCC through bioinformatics analysis and validated the results of bioinformatics by our data to address this problem.Results:The results of bioinformatics analysis found that DCTN2 was a significant prognostic factor in HCC,and high-level DCTN2 can predict poor patient survival in HCC.Cox regression analysis also suggested that DCTN2(hazard ratio=1.748,95%confidence interval 1.190-2.568,P=0.004)is an independent prognostic factor for patient survival.Western blot and quantitative reverse transcriptionpolymerase chain reaction assays confirmed that the protein and mRNA expression levels of DCTN2 were upregulated in HCC cell lines.The proliferation,invasion,and migration were decreased and cell apoptosis was enhanced after DCTN2 was knocked down in Huh7 and Hep3B cells.DCTN2 promoted the cell cycle progression through regulating the expression of cell cycle regulatory proteins cyclindependent kinase 4,Cyclin D1,and p21.Conclusions:We propose that DCTN2 can serve as a prognostic marker for HCC.DCTN2 acts as an oncogene and promotes the cell cycle progression through the G1/S phase-related signaling pathway.
