Ocadaic acid treatment alters the intracellular localization of caveolin-1 and caveolin-2 in HepG2 cells

A. Kiss, Erzsébet Botos, Ágnes Turi, Nándor Müllner, Péter Hollósi, I. Kovalszky

Research output: Contribution to journalArticle

Abstract

In this paper we provide evidences that protein phosphatases could regulate the intracellular localization of caveolin isoforms in a hepatoma cell line (HepG2). Ocadaic acid (OA) - a serine/threonine phosphatase inhibitor - was used in various concentrations (4nM and 100nM) to study the localization of caveolin-1 and caveolin-2 in HepG2 cells. Using fluorescent and confocal immunocytochemistry we have found that OA in both concentrations has significantly altered the intracellular localization and distribution of the caveolin-1 and caveolin-2 as well. in control (-OA treatment) the caveolin-1 was present in discrete punctate structures in the cytoplasm and also on the cell membrane. Caveolin-2 has partly overlapped with caveolin-1, but a significant amount caveolin-2 was detected around the nucleus. After OA (4 and 100 nM) treatment caveolin-1 has disappeared from the cell membrane, it was present mainly in the cytoplasm in larger vesicle or vacuole-like structures that were arranged along the cables of the cytoskeleton. In many cases caveolin-2 was found to colocalize with caveolin-1, but there was always a significant amount of caveolin-2 present around the nucleus. Immunoprecipitation and Western blot analysis revealed that in OA-treated cells a ∼24 kDa protein identified as caveolin-2 was strongly phosphorylated on tyrosine residues. The effect of OA was not reversible, since the removal of OA has not resulted in the dephosphorylation of caveolin-2 and the perinuclear localization of caveolin-2 remained. Our data indicate that phophorylation of caveolin-2 can alter not only the intracellular localization of caveolin isoforms but also the distribution of caveolae. The cytoskeleton seems to play an important role in the normal and altered distribution of caveolae, and the tyrosine phosphorylation or the absence of dephosphorylation of caveolin-2 isoform can inhibit the recycling of caveolae.

Original languageEnglish
Pages (from-to)11-17
Number of pages7
JournalActa Biologica Szegediensis
Volume47
Issue number1-4
Publication statusPublished - 2003

Fingerprint

Caveolin 2
Caveolin 1
Okadaic Acid
Hep G2 Cells
acid treatment
acids
dephosphorylation
cells
Caveolae
cytoskeleton
tyrosine
cell membranes
Therapeutics
cytoplasm
Caveolins
Protein Isoforms
Phosphoprotein Phosphatases
cables (equipment)
Cell membranes
Cytoskeleton

Keywords

  • Caveolae-cycle
  • Caveolin-2
  • Resident and elicited macrophages phosphatase inhibitors
  • Tyrosine phosphorylation

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Cell Biology
  • Neuroscience(all)
  • Applied Microbiology and Biotechnology

Cite this

Ocadaic acid treatment alters the intracellular localization of caveolin-1 and caveolin-2 in HepG2 cells. / Kiss, A.; Botos, Erzsébet; Turi, Ágnes; Müllner, Nándor; Hollósi, Péter; Kovalszky, I.

In: Acta Biologica Szegediensis, Vol. 47, No. 1-4, 2003, p. 11-17.

Research output: Contribution to journalArticle

Kiss, A. ; Botos, Erzsébet ; Turi, Ágnes ; Müllner, Nándor ; Hollósi, Péter ; Kovalszky, I. / Ocadaic acid treatment alters the intracellular localization of caveolin-1 and caveolin-2 in HepG2 cells. In: Acta Biologica Szegediensis. 2003 ; Vol. 47, No. 1-4. pp. 11-17.
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AU - Kiss, A.

AU - Botos, Erzsébet

AU - Turi, Ágnes

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AU - Hollósi, Péter

AU - Kovalszky, I.

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AB - In this paper we provide evidences that protein phosphatases could regulate the intracellular localization of caveolin isoforms in a hepatoma cell line (HepG2). Ocadaic acid (OA) - a serine/threonine phosphatase inhibitor - was used in various concentrations (4nM and 100nM) to study the localization of caveolin-1 and caveolin-2 in HepG2 cells. Using fluorescent and confocal immunocytochemistry we have found that OA in both concentrations has significantly altered the intracellular localization and distribution of the caveolin-1 and caveolin-2 as well. in control (-OA treatment) the caveolin-1 was present in discrete punctate structures in the cytoplasm and also on the cell membrane. Caveolin-2 has partly overlapped with caveolin-1, but a significant amount caveolin-2 was detected around the nucleus. After OA (4 and 100 nM) treatment caveolin-1 has disappeared from the cell membrane, it was present mainly in the cytoplasm in larger vesicle or vacuole-like structures that were arranged along the cables of the cytoskeleton. In many cases caveolin-2 was found to colocalize with caveolin-1, but there was always a significant amount of caveolin-2 present around the nucleus. Immunoprecipitation and Western blot analysis revealed that in OA-treated cells a ∼24 kDa protein identified as caveolin-2 was strongly phosphorylated on tyrosine residues. The effect of OA was not reversible, since the removal of OA has not resulted in the dephosphorylation of caveolin-2 and the perinuclear localization of caveolin-2 remained. Our data indicate that phophorylation of caveolin-2 can alter not only the intracellular localization of caveolin isoforms but also the distribution of caveolae. The cytoskeleton seems to play an important role in the normal and altered distribution of caveolae, and the tyrosine phosphorylation or the absence of dephosphorylation of caveolin-2 isoform can inhibit the recycling of caveolae.

KW - Caveolae-cycle

KW - Caveolin-2

KW - Resident and elicited macrophages phosphatase inhibitors

KW - Tyrosine phosphorylation

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