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α‐Tocopherol enhances degranulation in RBL‐2H3 mast cells
Author(s) -
Hemmerling Jana,
Nell Sandra,
Kipp Anna,
Schumann Sara,
Deubel Stefanie,
Haack Michael,
BrigeliusFlohé Regina
Publication year - 2010
Publication title -
molecular nutrition and food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.495
H-Index - 131
eISSN - 1613-4133
pISSN - 1613-4125
DOI - 10.1002/mnfr.200900462
Subject(s) - degranulation , ionomycin , phosphatase , microbiology and biotechnology , chemistry , protein tyrosine phosphatase , biochemistry , receptor , biology , phosphorylation , intracellular
Based on the observation that 3 months α‐tocopherol supplementation caused an up‐regulation of the mRNA of vesicular transport proteins in livers of mice, the functional relevance was investigated in RBL‐2H3 cells, a model for mast cell degranulation. In total, 24 h incubation with 100 μM α‐tocopherol enhanced the basal and phorbol‐12‐myristyl‐13‐acetate/ionomycin‐stimulated release of β‐hexosaminidase and cathepsin D as measured by enzymatic analysis as well as Western blotting and immunocytochemistry, respectively. β‐Tocopherol exerted the same effect, whereas α‐tocopheryl phosphate and trolox were inactive, indicating that both the side chain and the 6‐OH group at the chroman ring are essential for activation of degranulation. α‐Tocopherol did not induce mRNA expression of soluble NSF‐attachment protein receptor (soluble N ‐ethylmaleimide‐sensitive factor‐attachment protein receptor) proteins, such as N ‐ethylmaleimide sensitive fusion protein, complexin‐2, SNAP23 or syntaxin‐3, in the RBL‐2H3 cell model. In view of the well known α‐tocopherol‐mediated activation of protein phosphatases, which regulate soluble NSF‐attachment protein receptor activities by dephosphorylation, underlying mechanisms are discussed in terms of preventing oxidative inactivation of protein phosphatases and so far unknown functions in certain membrane domains.