Expression of caveolin-1 and -2 in differentiating PC12 cells and dorsal root ganglion neurons: caveolin-2 is up-regulated in response to cell injury.
Caveolae are cholesterol/sphingolipid-rich microdomains of the plasma membrane that have been implicated in signal transduction and vesicular trafficking. Caveolins are a family of caveolae-associated integral membrane proteins. Caveolin-1 and -2 show the widest range of expression, whereas caveolin-3 expression is restricted to muscle cell types. It has been previously reported that little or no caveolin mRNA species are detectable in the brain by Northern blot analyses or in neuroblastoma cell lines. However, it remains unknown whether caveolins are expressed within neuronal cells. Here we demonstrate the expression of caveolin-1 and -2 in differentiating PC12 cells and dorsal root ganglion (DRG) neurons by using mono-specific antibody probes. In PC12 cells, caveolin-1 expression is up-regulated on day 4 of nerve growth factor (NGF) treatment, whereas caveolin-2 expression is transiently up-regulated early in the differentiation program and then rapidly down-regulated. Interestingly, caveolin-2 is up-regulated in response to the mechanical injury of differentiated PC12 cells; up-regulation of caveolin-2 under these conditions is strictly dependent on continued treatment with NGF. Robust expression of caveolin-1 and -2 is also observed along the entire cell surface of DRG neurons, including high levels on growth cones. These findings demonstrate that neuronal cells express caveolins.
Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
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F
Galbiati
D
D
Volonte
O
O
Gil
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Zanazzi
J L
JL
Salzer
M
M
Sargiacomo
P E
PE
Scherer
J A
JA
Engelman
A
A
Schlegel
M
M
Parenti
T
T
Okamoto
M P
MP
Lisanti
D000818:Animals; D001483:Base Sequence; D051242:Caveolin 1; D051243:Caveolin 2; D022461:Caveolins; D002454:Cell Differentiation; D017931:DNA Primers / Q000235:genetics; D019922:GAP-43 Protein / Q000235:genetics; D005727:Ganglia, Spinal / Q000166:cytology / Q000293:injuries* / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics*; D009414:Nerve Growth Factors / Q000494:pharmacology; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D016716:PC12 Cells; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D015854:Up-Regulation / Q000187:drug effects
C495537:Cav1 protein, rat; D051242:Caveolin 1; D051243:Caveolin 2; D022461:Caveolins; D017931:DNA Primers; D019922:GAP-43 Protein; D008565:Membrane Proteins; D009414:Nerve Growth Factors; D012333:RNA, Messenger