title: Mammalian TRAPPIII Complex positively modulates the recruitment of Sec13/31 onto COPII vesicles.
abstract: The Transport protein particle (TRAPP) complex is a tethering factor for COPII vesicle. Of three forms of TRAPP (TRAPPI, II and III) complexes identified so far, TRAPPIII has been largely considered to play a role in autophagy. While depletion of TRAPPIII specific subunits caused defects in the early secretory pathway and TRAPPIII might interact with components of the COPII vesicle coat, its exact role remains to be determined. In this study, we studied the function of TRAPPIII in early secretory pathway using a TRAPPIII-specific subunit, TRAPPC12, as starting point. We found that TRAPPC12 was localized to the ER exit sites and ERGIC. In cells deleted with TRAPPC12, ERGIC and to a lesser extent, the Golgi became dispersed. ER-to-Golgi transport was also delayed. TRAPPC12, but not TRAPPC8, bound to Sec13/Sec31A tetramer but each Sec protein alone could not interact with TRAPPC12. TRAPPIII positively modulated the assembly of COPII outer layer during COPII vesicle formation. These results identified a novel function of TRAPPIII as a positive modulator of the outer layer of the COPII coat.
authors.affiliation: School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China.
authors.forename: Shan
authors.initials: S
authors.lastname: Zhao
authors.affiliation: School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China.
authors.forename: Chun Man
authors.initials: CM
authors.lastname: Li
authors.affiliation: School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China.
authors.forename: Xiao Min
authors.initials: XM
authors.lastname: Luo
authors.affiliation: School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China.
authors.forename: Gavin Ka Yu
authors.initials: GK
authors.lastname: Siu
authors.affiliation: School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China.
authors.forename: Wen Jia
authors.initials: WJ
authors.lastname: Gan
authors.affiliation: School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China.|Department of anesthesia, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, P.R. China.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of anesthesia, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, P.R. China.
authors.forename: William K K
authors.initials: WK
authors.lastname: Wu
authors.affiliation: School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China.|Epithelial Cell Biology Research Centre, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China.
authors.forename: Hsiao Chang
authors.initials: HC
authors.lastname: Chan
authors.affiliation: School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China.|Epithelial Cell Biology Research Centre, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China.
authors.forename: Sidney
authors.initials: S
authors.lastname: Yu
mesh_terms: D000818:Animals; D019556:COS Cells; D002352:Carrier Proteins / Q000378:metabolism*; D002522:Chlorocebus aethiops; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D011485:Protein Binding; D022142:Secretory Vesicles / Q000378:metabolism*; D033921:Vesicular Transport Proteins / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; C507456:SEC13 protein, human; C507455:SEC31A protein, human; C000629061:TRAPPC12 protein, human; D033921:Vesicular Transport Proteins; C406327:transport protein particle, TRAPP