title: Interaction of scavenger receptor class B type I with peroxisomal targeting receptor Pex5p.
abstract: Scavenger receptor class B type I (SR-BI) is an HDL receptor that mediates selective HDL lipid uptake. Peroxisomes play an important role in lipid metabolism and peroxisomal targeting signal type 1 (PTS1)-containing proteins are translocated to peroxisomes by the peroxisomal targeting import receptor, Pex5p. We have previously identified a PTS1 motif in the intracellular domain of rat SR-BI. Here, we examine the possible interaction between Pex5p and SR-BI. Expression of a Flag-tagged intracellular domain of SR-BI resulted in translocation to the peroxisome as demonstrated by double labeling with anti-Flag IgG and anti-catalase IgG analyzed by confocal microscopy. Immunoprecipitation experiments with anti-SR-BI antibody showed that Pex5p co-precipitated with SR-BI. However, when an antibody against Pex5p was used for immunoprecipitation, only the 57kDa, non-glycosylated form, of SR-BI co-precipitated. We conclude that the PTS1 domain of SR-BI is functional and can mediate peroxisomal interaction via Pex5p, in vitro.
authors.affiliation: Research Centre for Endocrinology and Metabolism (RCEM), Department of Internal Medicine, The Sahlgrenska Academy at Göteborg University, S-413 45, Göteborg, Sweden. Magnus.Johnson@medic.gu.se
authors.forename: Magnus S C
authors.initials: MS
authors.lastname: Johnson
authors.forename: Jenny M
authors.initials: JM
authors.lastname: Johansson
authors.forename: Per Arne
authors.initials: PA
authors.lastname: Svensson
authors.forename: Maria A I
authors.initials: MA
authors.lastname: Aberg
authors.forename: Peter S
authors.initials: PS
authors.lastname: Eriksson
authors.forename: Lena M S
authors.initials: LM
authors.lastname: Carlsson
authors.forename: Björn
authors.initials: B
authors.lastname: Carlsson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D018955:CD36 Antigens / Q000737:chemistry* / Q000378:metabolism*; D016466:CHO Cells; D019556:COS Cells; D002522:Chlorocebus aethiops; D006224:Cricetinae; D003412:Cricetulus; D008075:Lipoproteins, HDL / Q000378:metabolism*; D008565:Membrane Proteins; D008967:Molecular Biology; D000074435:Peroxisome-Targeting Signal 1 Receptor; D020675:Peroxisomes / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry* / Q000378:metabolism*; D011971:Receptors, Immunologic; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; D051122:Scavenger Receptors, Class B; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship
chemical_list: D018955:CD36 Antigens; D008075:Lipoproteins, HDL; D008565:Membrane Proteins; D000074435:Peroxisome-Targeting Signal 1 Receptor; D018160:Receptors, Cytoplasmic and Nuclear; D011971:Receptors, Immunologic; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; C454739:Scarb1 protein, mouse; C495125:Scarb1 protein, rat; D051122:Scavenger Receptors, Class B