title: Self-interaction of human Pex11pβ during peroxisomal growth and division.
abstract: Pex11 proteins are involved in membrane elongation and division processes associated with the multiplication of peroxisomes. Human Pex11pβ has recently been linked to a new disorder affecting peroxisome morphology and dynamics. Here, we have analyzed the exact membrane topology of Pex11pβ. Studies with an epitope-specific antibody and protease protection assays show that Pex11pβ is an integral membrane protein with two transmembrane domains flanking an internal region exposed to the peroxisomal matrix and N- and C-termini facing the cytosol. A glycine-rich internal region within Pex11pβ is dispensable for peroxisome membrane elongation and division. However, we demonstrate that an amphipathic helix (Helix 2) within the first N-terminal 40 amino acids is crucial for membrane elongation and self-interaction of Pex11pβ. Interestingly, we find that Pex11pβ self-interaction strongly depends on the detergent used for solubilization. We also show that N-terminal cysteines are not essential for membrane elongation, and that putative N-terminal phosphorylation sites are dispensable for Pex11pβ function. We propose that self-interaction of Pex11pβ regulates its membrane deforming activity in conjunction with membrane lipids.
authors: Centre for Cell Biology and Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal.
authors: Nina A
authors: NA
authors: Bonekamp
authors: Sandra
authors: S
authors: Grille
authors: Maria Joao
authors: MJ
authors: Cardoso
authors: Monica
authors: M
authors: Almeida
authors: Miguel
authors: M
authors: Aroso
authors: Silvia
authors: S
authors: Gomes
authors: Ana Cristina
authors: AC
authors: Magalhaes
authors: Daniela
authors: D
authors: Ribeiro
authors: Markus
authors: M
authors: Islinger
authors: Michael
authors: M
authors: Schrader
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D006801:Humans; D007425:Intracellular Membranes / Q000737:chemistry / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D020675:Peroxisomes / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D054730:Protein Interaction Domains and Motifs; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D014162:Transfection
chemical_list: D008565:Membrane Proteins; C490453:PEX11B protein, human; D011993:Recombinant Fusion Proteins