title: The first minutes in the life of a peroxisomal matrix protein.
abstract: In the field of intracellular protein sorting, peroxisomes are most famous by their capacity to import oligomeric proteins. The data supporting this remarkable property are abundant and, understandably, have inspired a variety of hypothetical models on how newly synthesized (cytosolic) proteins reach the peroxisome matrix. However, there is also accumulating evidence suggesting that many peroxisomal oligomeric proteins actually arrive at the peroxisome still as monomers. In support of this idea, recent data suggest that PEX5, the shuttling receptor for peroxisomal matrix proteins, is also a chaperone/holdase, binding newly synthesized peroxisomal proteins in the cytosol and blocking their oligomerization. Here we review the data behind these two different perspectives and discuss their mechanistic implications on this protein sorting pathway.
authors.affiliation: Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Portugal; Organelle Biogenesis and Function Group, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal; Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal.
authors.forename: Ana F
authors.initials: AF
authors.lastname: Dias
authors.affiliation: Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Portugal; Organelle Biogenesis and Function Group, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.
authors.forename: Tânia
authors.initials: T
authors.lastname: Francisco
authors.affiliation: Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Portugal; Organelle Biogenesis and Function Group, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.
authors.forename: Tony A
authors.initials: TA
authors.lastname: Rodrigues
authors.affiliation: Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Portugal; Organelle Biogenesis and Function Group, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.
authors.forename: Cláudia P
authors.initials: CP
authors.lastname: Grou
authors.affiliation: Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Portugal; Organelle Biogenesis and Function Group, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal; Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal. Electronic address: jazevedo@ibmc.up.pt.
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Azevedo
mesh_terms: D000818:Animals; D005057:Eukaryotic Cells / Q000737:chemistry / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D000074437:Peroxisomal Targeting Signal 2 Receptor; D000074435:Peroxisome-Targeting Signal 1 Receptor; D020675:Peroxisomes / Q000737:chemistry / Q000378:metabolism*; D010944:Plants / Q000737:chemistry / Q000378:metabolism; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors
chemical_list: C000614264:PEX5 protein, human; C000614269:PEX7 protein, human; D000074437:Peroxisomal Targeting Signal 2 Receptor; D000074435:Peroxisome-Targeting Signal 1 Receptor; D020033:Protein Isoforms; D018160:Receptors, Cytoplasmic and Nuclear
keywords: PEX5; PEX7; PTS1; PTS2; Peroxisome; Protein translocation