title: Hydrophobic handoff for direct delivery of peroxisome tail-anchored proteins.
abstract: Tail-anchored (TA) proteins are inserted into membranes post-translationally through a C-terminal transmembrane domain (TMD). The PEX19 protein binds peroxisome TA proteins in the cytoplasm and delivers them to the membrane through the PEX3 receptor protein. An amphipathic segment in PEX19 promotes docking on PEX3. However, how this leads to substrate insertion is unknown. Here we reconstitute peroxisome TA protein biogenesis into two sequential steps of substrate TMD engagement and membrane insertion. We identify a series of previously uncharacterized amphipathic segments in PEX19 and identify one whose hydrophobicity is required for membrane insertion, but not TMD chaperone activity or PEX3 binding. A membrane-proximal hydrophobic surface of PEX3 promotes an unconventional form of membrane intercalation, and is also required for TMD insertion. Together, these data support a mechanism in which hydrophobic moieties in the TMD chaperone and its membrane-associated receptor act in a concerted manner to prompt TMD release and membrane insertion.
authors.affiliation: Temasek Life Sciences Laboratory, Department of Biological Sciences, National University of Singapore, Singapore 117604, Singapore.
authors.forename: Yinxiao
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Temasek Life Sciences Laboratory, Department of Biological Sciences, National University of Singapore, Singapore 117604, Singapore.
authors.forename: Laurent
authors.initials: L
authors.lastname: Pieuchot
authors.affiliation: Temasek Life Sciences Laboratory, Department of Biological Sciences, National University of Singapore, Singapore 117604, Singapore.
authors.forename: Rachel Ann
authors.initials: RA
authors.lastname: Loh
authors.affiliation: Temasek Life Sciences Laboratory, Department of Biological Sciences, National University of Singapore, Singapore 117604, Singapore.
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.affiliation: Temasek Life Sciences Laboratory, Department of Biological Sciences, National University of Singapore, Singapore 117604, Singapore.
authors.forename: Teuku Mahfuzh Aufar
authors.initials: TM
authors.lastname: Kari
authors.affiliation: Temasek Life Sciences Laboratory, Department of Biological Sciences, National University of Singapore, Singapore 117604, Singapore.
authors.forename: Jie Yun
authors.initials: JY
authors.lastname: Wong
authors.affiliation: Temasek Life Sciences Laboratory, Department of Biological Sciences, National University of Singapore, Singapore 117604, Singapore.
authors.forename: Gregory
authors.initials: G
authors.lastname: Jedd
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007668:Kidney; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009492:Neurospora crassa / Q000235:genetics / Q000378:metabolism; D020675:Peroxisomes / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D021381:Protein Transport; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D000097573:Red Fluorescent Protein
chemical_list: D005656:Fungal Proteins; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D008565:Membrane Proteins; D011994:Recombinant Proteins; D000097573:Red Fluorescent Protein