title: Multiple Domains in PEX16 Mediate Its Trafficking and Recruitment of Peroxisomal Proteins to the ER.
abstract: Peroxisomes rely on a diverse array of mechanisms to ensure the specific targeting of their protein constituents. Peroxisomal membrane proteins (PMPs), for instance, are targeted by at least two distinct pathways: directly to peroxisomes from their sites of synthesis in the cytosol or indirectly via the endoplasmic reticulum (ER). However, the extent to which each PMP targeting pathway is involved in the maintenance of pre-existing peroxisomes is unclear. Recently, we showed that human PEX16 plays a critical role in the ER-dependent targeting of PMPs by mediating the recruitment of two other PMPs, PEX3 and PMP34, to the ER. Here, we extend these results by carrying out a comprehensive mutational analysis of PEX16 aimed at gaining insights into the molecular targeting signals responsible for its ER-to-peroxisome trafficking and the domain(s) involved in PMP recruitment function at the ER. We also show that the recruitment of PMPs to the ER by PEX16 is conserved in plants. The implications of these results in terms of the function of PEX16 and the role of the ER in peroxisome maintenance in general are discussed.
authors.affiliation: Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada M5G 0A4.|Department of Biochemistry, University of Toronto, Toronto, ON, Canada M5G 1A8.
authors.forename: Rong
authors.initials: R
authors.lastname: Hua
authors.affiliation: Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada N1G 2W1.
authors.forename: Satinder K
authors.initials: SK
authors.lastname: Gidda
authors.affiliation: Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada M5G 0A4.
authors.forename: Alexander
authors.initials: A
authors.lastname: Aranovich
authors.affiliation: Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada N1G 2W1.
authors.forename: Robert T
authors.initials: RT
authors.lastname: Mullen
authors.affiliation: Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada M5G 0A4.|Department of Biochemistry, University of Toronto, Toronto, ON, Canada M5G 1A8.
authors.forename: Peter K
authors.initials: PK
authors.lastname: Kim
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D000074401:Peroxins; D020675:Peroxisomes / Q000378:metabolism*; D021382:Protein Sorting Signals; D017434:Protein Structure, Tertiary
chemical_list: D029681:Arabidopsis Proteins; D000074401:Peroxins; C118605:Pex16 protein, Arabidopsis; D021382:Protein Sorting Signals
keywords: ER; PEX16; PEX19; PEX3; membrane targeting; organelle biogenesis; peroxisomal membrane protein; peroxisomes; protein targeting signal; protein trafficking