Caveolin moves from caveolae to the Golgi apparatus in response to cholesterol oxidation.

Smart, Elizabeth; Ying, Yun Shu; Conrad, Patricia A.; Anderson, Richard G. W.

doi:10.1083/jcb.127.5.1185

Cited by 404 publications

(381 citation statements)

References 36 publications

Supporting

Mentioning

346

Contrasting

Unclassified

Order By: Relevance

“…E-mail: Parton@EMBL-Heidelberg.de function as shown by treatment of cells with cholesterol-binding agents [17] and may be recruited by V-caveolin. In addition, treatment of cells with cholesterol oxidase causes redistribution of V-caveolin from the cell surface [18]. Our recent results demonstrate a direct role for V-caveolin in caveolae formation.…”

Section: Introductionsupporting

confidence: 52%

M‐caveolin, a muscle‐specific caveolin‐related protein

1995

View full text Add to dashboard Cite

Caveolae, small invaginations of the plasma membrane, are a characteristic feature of many mammalian cells. The best-characterised caveolar protein is the integral membrane protein, VIP21-caveolin. We now describe a novel homologue of VIP21-caveolin, M-caveolin, which is expressed exclusively in muscle. M-caveolin was shown to be expressed in differentiated myotubes but not myoblasts. Epitope-tagged M-caveolin expressed in non-muscle cells was targetted to surface caveolae where it colocalized with endogenous VIP21-caveolin. M-caveolin may play a specialised role in the caveolae of muscle cells.

show abstract

Section: Introductionsupporting

confidence: 52%

M‐caveolin, a muscle‐specific caveolin‐related protein

1995

View full text Add to dashboard Cite

show abstract

“…Preparation of Caveolae-enriched Membrane Fractions-NIH 3T3 cells (untransfected or stably expressing c-Src) were washed with PBS and lysed with 2 ml of ice-cold MES-buffered saline (MBS, 25 mM MES, pH 6.5, 0.15 M NaCl) containing 1% (v/v) Triton X-100 (11,14,15,(22)(23)(24)(25)(26)(27)(28)(29). Homogenization was carried out with 10 strokes of a loosefitting Dounce homogenizer.…”

Section: Methodsmentioning

confidence: 99%

Src-induced Phosphorylation of Caveolin-2 on Tyrosine 19

Lee

Park

Wang

et al. 2002

Journal of Biological Chemistry

View full text Add to dashboard Cite

Caveolin-2 is the least well studied member of the caveolin gene family. It is believed that caveolin-2 is an "accessory protein" that functions in conjunction with caveolin-1. At the level of the ER, caveolin-2 interacts with caveolin-1 to form a high molecular mass heterooligomeric complex that is targeted to lipid rafts and drives the formation of caveolae. However, caveolin-2 is not required for caveolae formation, implying that it may fulfill some unknown regulatory role. Here, we present the first evidence that caveolin-2 is a phosphoprotein. We show that caveolin-2 undergoes Src-induced phosphorylation on tyrosine 19. To study this phosphorylation event in vivo, we generated a novel phospho-specific antibody probe that only recognizes phosphocaveolin-2 (Tyr(P) 19 ). We then used NIH-3T3 cells stably overexpressing c-Src to examine the localization and biochemical properties of phosphocaveolin-2 (Tyr(P) 19 ). Our results indicate that phosphocaveolin-2 (Tyr(P) 19 ) is localized near focal adhesions, remains associated with lipid rafts/caveolae, but no longer forms a high molecular mass hetero-oligomer with caveolin-1. Instead, phosphocaveolin-2 (Tyr(P) 19 ) behaves as a monomer/dimer in velocity gradients. Thus, we conclude that the tyrosine phosphorylation of caveolin-2 (Tyr(P) 19 ) may function as a signal that is recognized by the cellular machinery to induce the dissociation of caveolin-2 from caveolin-1 oligomers. We also demonstrate that (i) insulin-stimulation of adipocytes and (ii) integrin ligation of endothelial cells can both induce the tyrosine phosphorylation of caveolin-2 (Tyr(P) 19 ). During integrin ligation, phosphocaveolin-2 (Tyr(P) 19 ) co-localizes with activated FAK at focal adhesions. Thus, phosphocaveolin-2 (Tyr(P) 19 ) may function as a docking site for Src homology domain-2 (SH2) domain containing proteins during signal transduction. In support of this notion, we identify several SH2 domain containing proteins, namely c-Src, NCK, and Ras-GAP, that interact with caveolin-2 in a phosphorylation-dependent manner. Furthermore, our co-immunoprecipitation experiments show that caveolin-2 and Ras-GAP are constitutively associated in c-Src expressing NIH-3T3 cells, but not in untransfected NIH-3T3 cells.Receptor tyrosine kinases (RTKs) 1 contain one or more autophosphorylation sites. Upon ligand binding, a specific receptor is activated and undergoes autophosphorylation on specific tyrosine residues. One known function for tyrosine phosphorylation is to confer docking sites for Src homology domain-2 (SH2)-containing proteins. Numerous downstream signaling molecules possessing either intrinsic kinase activity or an adapter function are then recruited to the plasma membrane and utilize their SH2 domains to form hetero-oligomeric signaling complexes with activated RTKs.Numerous RTKs, such as epidermal growth factor receptor (EGF-R), platelet-derived growth factor receptor (PDGF-R), and insulin receptor (Ins-R), as well as non-receptor tyrosine kinases (NRTKs; Src-family tyrosine kinases) are ...

show abstract

“…It is important to note that not only the quantity, but also the chemical structure of the sterol and the presence of cholesterol oxidation products are known to significantly affect the structure and/or function of model membranes (rev. in (54,55,70,72,73), biological membranes (13,(74)(75)(76)(77)(78)(79)(80), lipid raft/caveolae (58,(81)(82)(83)(84)(85)(86)(87)(88), and cholesterol-requiring plasma membrane receptors (66,(89)(90)(91). Because of this sensitivity it is essential that fluorescent sterols such as DHE not contain other sterols (e.g.…”

Section: Effect Of Sterol Structure and Purity On Sterol Architecturementioning

confidence: 99%

Fluorescence Techniques Using Dehydroergosterol to Study Cholesterol Trafficking

McIntosh

Atshaves

Huang

et al. 2008

Lipids

View full text Add to dashboard Cite

Cholesterol itself has very few structural/chemical features suitable for real-time imaging in living cells. Thus, the advent of dehydroergosterol [ergosta-5,7,9(11),22-tetraen-3β-ol, DHE] the fluorescent sterol most structurally and functionally similar to cholesterol to date, has proven to be a major asset for real-time probing/elucidating the sterol environment and intracellular sterol trafficking in living organisms. DHE is a naturally-occurring, fluorescent sterol analog that faithfully mimics many of the properties of cholesterol. Because these properties are very sensitive to sterol structure and degradation, such studies require the use of extremely pure (>98%) quantities of fluorescent sterol. DHE is readily bound by cholesterol-binding proteins, is incorporated into lipoproteins (from the diet of animals or by exchange in vitro), and for real-time imaging studies is easily incorporated into cultured cells where it co-distributes with endogenous sterol. Incorporation from an ethanolic stock solution to cell culture media is effective, but this process forms an aqueous dispersion of dehydroergosterol crystals which can result in endocytic cellular uptake and distribution into lysosomes which is problematic in imaging DHE at the plasma membrane of living cells. In contrast, monomeric DHE can be incorporated from unilamellar vesicles by exchange/fusion with the plasma membrane or from DHE-methyl-β-cyclodextrin (DHE-MβCD) complexes by exchange with the plasma membrane. Both of the latter techniques can deliver large quantities of monomeric dehydroergosterol with significant distribution into the plasma membrane. The properties and behavior of DHE in protein-binding, lipoproteins, model membranes, biological membranes, lipid rafts/caveolae, and real-time imaging in living cells indicate that this naturally-occurring fluorescent sterol is a useful mimic for probing the properties of cholesterol in these systems. Keywordsdehydroergosterol; cholesterol; ergosterol; fluorescent sterols; microscopy Historical PerspectiveIn order to resolve the dynamics and factors governing cholesterol trafficking within cells, it is important to recognize that the cholesterol molecule has very few polar constituents (Fig. 1A). Consequently, cholesterol is poorly soluble in aqueous environments such as cytosol as evidenced by critical micellar concentrations of cholesterol and other sterols being very low, *To whom correspondence should be addressed: Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 862-1433, FAX: (979) NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript near 20-30 nM (1-5). The physiological impact of cholesterol's low aqueous solubility is that spontaneous cholesterol desorption from the cytofacial leaflet of the plasma membrane or lysosomal membrane into the cytosol for transfer to intracellular sites for esterification, oxidation, or secretion is extremely slow (t 1/2 3 hours-days) (6-9). Therefore, it is important to resolve factors...

show abstract

Caveolin moves from caveolae to the Golgi apparatus in response to cholesterol oxidation.

Cited by 404 publications

References 36 publications

M‐caveolin, a muscle‐specific caveolin‐related protein

M‐caveolin, a muscle‐specific caveolin‐related protein

Src-induced Phosphorylation of Caveolin-2 on Tyrosine 19

Fluorescence Techniques Using Dehydroergosterol to Study Cholesterol Trafficking

Contact Info

Product

Resources

About