Caveolin-1 expression in Schwann cells.
Caveolae are non-clathrin-coated invaginations of the plasma membrane, which are present in most cell types. An integral component of caveolae is the caveolin family of related proteins, which not only forms the structural framework of caveolae, but also likely subserves its functional roles, including regulation of signal transduction and cellular transport, in particular, cholesterol trafficking. Although caveolae have been identified ultrastructurally in the peripheral nervous system (PNS), caveolin expression has not previously been studied. To date, three caveolin genes have been reported. Here, we show for the first time that caveolin-1 is expressed by Schwann cells (SC) as well as several SC-derived cell lines. Caveolin-1 is enriched in the buoyant, detergent-insoluble membranes of rat sciatic nerve (SN) and SC, a hallmark of the caveolar compartment. Caveolin-1 exists as both soluble and insoluble forms in rat SN and SC, and localizes to SC cytoplasm and abaxonal myelin. SC caveolin-1 decreases after axotomy, when SC revert to a premyelinating phenotype. We speculate that caveolin-1 may regulate signal transduction and/or cholesterol transport in myelinating SC.
Department of Neurology, University of Michigan, Ann Arbor 48109, USA. dmiko@umich.edu
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Mikol
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Hong
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HL
Cheng
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Feldman
D000818:Animals; D019771:Axotomy / Q000009:adverse effects; D051242:Caveolin 1; D022461:Caveolins; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D006801:Humans; D008565:Membrane Proteins / Q000032:analysis* / Q000187:drug effects; D018993:Myelin P0 Protein / Q000187:drug effects; D009447:Neuroblastoma / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D012583:Schwann Cells / Q000737:chemistry* / Q000502:physiology; D012584:Sciatic Nerve / Q000737:chemistry* / Q000502:physiology; D014407:Tumor Cells, Cultured
C495540:CAV1 protein, human; C495537:Cav1 protein, rat; D051242:Caveolin 1; D022461:Caveolins; D008565:Membrane Proteins; D018993:Myelin P0 Protein; D005576:Colforsin