Association of a Photoreceptor-Specific Tetraspanin Protein, ROM-1, with Triton X-100-Resistant Membrane Rafts from Rod Outer Segment Disk Membranes

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dc.contributor.authorBoesze-Battaglia, Kathleen
dc.contributor.authorDispoto, Janice
dc.contributor.authorKahoe, Mary Anne
dc.date2023-05-18T03:59:18.000
dc.date.accessioned2023-05-22T13:14:56Z
dc.date.available2023-05-22T13:14:56Z
dc.date.issued2002-01-01
dc.date.submitted2022-11-09T12:43:49-08:00
dc.description.abstractThis study reports the isolation and characterization of a Triton X-100-resistant membrane fraction from homogenates of rod outer segment (ROS) disk membranes purified free of the surrounding plasma membrane. A portion of the ROS disk membrane was found to be resistant to Triton X-100 extraction at 4 °C. This detergent-resistant fraction was isolated as a low buoyant density band on sucrose density gradients and exhibited an increase in light scattering detected at 600 nm. Biochemical analysis of the Triton X-100-resistant fraction showed it to be enriched in cholesterol and sphingomyelin relative to phospholipid and in phospholipid relative to protein compared with the soluble fraction. The Triton X-100-resistant membranes described herein did not arise simply from partial solubilization of the ROS disk membranes because detergent-treated low buoyant density fractions isolated from homogenates with octyl glucopyranoside had cholesterol and sphingomyelin content indistinguishable from that of solubilized ROS disk homogenates. Analysis of proteins associated with the Triton X-100-resistant fraction showed it to be enriched in the rim-specific protein ROM-1 and caveolin; surprisingly, the fusion protein peripherin/rds (where rds is retinal degeneration slow), also localized to the disk rim, was entirely absent from the membrane raft domain. The lipid profiles of the Triton X-100-resistant membranes were virtually identical in preparations homogenized in either the light or dark. Slightly more ROM-1 was recovered from samples prepared in the light (23%) than from samples prepared in the dark (13%), but peripherin/rds could not be detected in either preparation. When the Triton X-100-resistant membranes were treated with methyl-β-cyclodextran to deplete membrane cholesterol, the resultant membranes contained slightly lower levels of ROM-1, specifically in the dimeric form. Cholesterol depletion also resulted in the collapse of the large caveolin complex to monomeric caveolae. The results presented herein characterize a pool of ROM-1, a photoreceptor tetraspanin protein, that may play a regulatory role in peripherin/rds-dependent fusion.
dc.identifier.urihttps://repository.upenn.edu/handle/20.500.14332/9082
dc.legacy.articleid1657
dc.legacy.fields10.1074/jbc.M207111200
dc.legacy.fulltexturlhttps://repository.upenn.edu/cgi/viewcontent.cgi?article=1657&context=dental_papers&unstamped=1
dc.source.beginpage41843
dc.source.endpage41849
dc.source.issue354
dc.source.issue44
dc.source.journalDepartmental Papers (Dental)
dc.source.journaltitleJournal of Biological Chemistry
dc.source.peerreviewedtrue
dc.source.statuspublished
dc.source.volume277
dc.subject.otherDentistry
dc.titleAssociation of a Photoreceptor-Specific Tetraspanin Protein, ROM-1, with Triton X-100-Resistant Membrane Rafts from Rod Outer Segment Disk Membranes
dc.typeArticle
digcom.contributor.authorBoesze-Battaglia, Kathleen
digcom.contributor.authorDispoto, Janice
digcom.contributor.authorKahoe, Mary Anne
digcom.identifierdental_papers/354
digcom.identifier.contextkey32167675
digcom.identifier.submissionpathdental_papers/354
digcom.typearticle
dspace.entity.typePublication
upenn.schoolDepartmentCenterDepartmental Papers (Dental)
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