title: Structural and functional characterization of ybr137wp implicates its involvement in the targeting of tail-anchored proteins to membranes.
abstract: Nearly 5% of membrane proteins are guided to nuclear, endoplasmic reticulum (ER), mitochondrial, Golgi, or peroxisome membranes by their C-terminal transmembrane domain and are classified as tail-anchored (TA) membrane proteins. In Saccharomyces cerevisiae, the guided entry of TA protein (GET) pathway has been shown to function in the delivery of TA proteins to the ER. The sorting complex for this pathway is comprised of Sgt2, Get4, and Get5 and facilitates the loading of nascent tail-anchored proteins onto the Get3 ATPase. Multiple pulldown assays also indicated that Ybr137wp associates with this complex in vivo. Here, we report a 2.8-Å-resolution crystal structure for Ybr137wp from Saccharomyces cerevisiae. The protein is a decamer in the crystal and also in solution, as observed by size exclusion chromatography and analytical ultracentrifugation. In addition, isothermal titration calorimetry indicated that the C-terminal acidic motif of Ybr137wp interacts with the tetratricopeptide repeat (TPR) domain of Sgt2. Moreover, an in vivo study demonstrated that Ybr137wp is induced in yeast exiting the log phase and ameliorates the defect of TA protein delivery and cell viability derived by the impaired GET system under starvation conditions. Therefore, this study suggests a possible role for Ybr137wp related to targeting of tail-anchored proteins.
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.
authors.forename: Yi-Hung
authors.initials: YH
authors.lastname: Yeh
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan Molecular Cell Biology, Taiwan International Graduate Program, Graduate Institute of Life Sciences, National Defense Medical Center and Academia Sinica, Taipei, Taiwan.
authors.forename: Tai-Wen
authors.initials: TW
authors.lastname: Lin
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan.
authors.forename: Yi-Chuan
authors.initials: YC
authors.lastname: Li
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.
authors.forename: Jung-Yu
authors.initials: JY
authors.lastname: Tung
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.
authors.forename: Cheng-Yuan
authors.initials: CY
authors.lastname: Lin
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan hsiao@gate.sinica.edu.tw.
authors.forename: Chwan-Deng
authors.initials: CD
authors.lastname: Hsiao
mesh_terms: D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism*; D018360:Crystallography, X-Ray; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D008565:Membrane Proteins; D029701:Saccharomyces cerevisiae Proteins; C520576:Sgt2 protein, S cerevisiae; C000594518:ybr137wp protein, S cerevisiae