Survival of memory B lymphocytes is tightly linked to the integrity of the Bcl-2 protein and is regulated by a nerve growth factor (NGF) autocrine circuit. In factor-starved memory B cells, the addition of exogenous NGF promptly induced p38 mitogen-activated protein kinase (MAPK), but not c-Jun N-terminal kinase (JNK), dephosphorylation. Conversely, withdrawal of endogenous NGF was followed by p38 MAPK activation and translocation onto mitochondria, whereby it combined with and phosphorylated Bcl-2, as assessed by co-immunoprecipitation and kinase assays in vivo and in vitro. Mitochondria isolated from human memory B cells, then exposed to recombinant p38 MAPK, released cytochrome c, as did mitochondria from Bcl-2-negative MDCK cells loaded with recombinant Bcl-2. Apoptosis induced by NGF neutralization could be blocked by the specific p38 MAPK inhibitor SB203580 or by Bcl-2 mutations in Ser-87 or Thr-56. These data demonstrate that the molecular mechanisms underlying the survival factor function of NGF critically rely upon the continuous inactivation of p38 MAPK, a Bcl-2-modifying enzyme.

NGF inhibits apoptosis in memory B lymphocytes via inactivation of p38 MAPK, prevention of Bcl-2 phosphorylation and cytochrome c release / TORCIA M; DE CHIARA G; NENCIONI L; AMMENDOLA S; LABARDI D; LUCIBELLO M; ROSINI P; MARLIER LN; BONINI P; DELLO SBARBA P; PALAMARA AT; ZAMBRANO N; RUSSO T; GARACI E; F. COZZOLINO. - In: THE JOURNAL OF BIOLOGICAL CHEMISTRY. - ISSN 0021-9258. - STAMPA. - 276:(2001), pp. 39027-39036.

NGF inhibits apoptosis in memory B lymphocytes via inactivation of p38 MAPK, prevention of Bcl-2 phosphorylation and cytochrome c release.

TORCIA, MARIA;ROSINI, PAOLO;BONINI, PAOLO;DELLO SBARBA, PERSIO;COZZOLINO, FEDERICO
2001

Abstract

Survival of memory B lymphocytes is tightly linked to the integrity of the Bcl-2 protein and is regulated by a nerve growth factor (NGF) autocrine circuit. In factor-starved memory B cells, the addition of exogenous NGF promptly induced p38 mitogen-activated protein kinase (MAPK), but not c-Jun N-terminal kinase (JNK), dephosphorylation. Conversely, withdrawal of endogenous NGF was followed by p38 MAPK activation and translocation onto mitochondria, whereby it combined with and phosphorylated Bcl-2, as assessed by co-immunoprecipitation and kinase assays in vivo and in vitro. Mitochondria isolated from human memory B cells, then exposed to recombinant p38 MAPK, released cytochrome c, as did mitochondria from Bcl-2-negative MDCK cells loaded with recombinant Bcl-2. Apoptosis induced by NGF neutralization could be blocked by the specific p38 MAPK inhibitor SB203580 or by Bcl-2 mutations in Ser-87 or Thr-56. These data demonstrate that the molecular mechanisms underlying the survival factor function of NGF critically rely upon the continuous inactivation of p38 MAPK, a Bcl-2-modifying enzyme.
2001
276
39027
39036
TORCIA M; DE CHIARA G; NENCIONI L; AMMENDOLA S; LABARDI D; LUCIBELLO M; ROSINI P; MARLIER LN; BONINI P; DELLO SBARBA P; PALAMARA AT; ZAMBRANO N; RUSSO...espandi
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/206719
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