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Role of intracellular Ca 2+ and calmodulin/MAP kinase kinase/extracellular signal‐regulated protein kinase signalling pathway in the mitogenic and antimitogenic effect of nitric oxide in glia‐ and neurone‐derived cell lines
Author(s) -
Meini Antonella,
Garcia Julian Blanco,
Pessina Gian Paolo,
Aldinucci Carlo,
Frosini Maria,
Palmi Mitri
Publication year - 2006
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2006.04705.x
Subject(s) - mapk/erk pathway , kinase , protein kinase a , microbiology and biotechnology , mitogen activated protein kinase , extracellular , intracellular , mitogen activated protein kinase kinase , chemistry , signal transduction , calmodulin , mitogen activated protein kinase 3 , biology , biochemistry , enzyme
To elucidate the mechanism of cell growth regulation by nitric oxide (NO) and the role played in it by Ca 2+ , we studied the relationship among intracellular Ca 2+ concentration ([Ca 2+ ] i ), mitogen‐activated protein kinases [extracellular signal‐regulated protein kinase (ERK)] and proliferation in cell lines exposed to different levels of NO. Data showed that NO released by low [(z)‐1‐[2‐aminiethyl]‐N‐[2‐ammonioethyl]amino]diazen‐1‐ium‐1,2diolate (DETA/NO) concentrations (10 µ m ) determined a gradual, moderate elevation in [Ca 2+ ] i (46.8 ± 7.2% over controls) which paralleled activation of ERK and potentiation of cell division. Functionally blocking Ca 2+ or inhibiting calmodulin or MAP kinase kinase activities prevented ERK activation and antagonized the mitogenic effect of NO. Experimental conditions favouring Ca 2+ entry into cells led to increased [Ca 2+ ] i (189.5 ± 4.8%), ERK activation and cell division. NO potentiated the Ca 2+ elevation (358 ± 16.8%) and ERK activation leading to expression of p21 Cip1 and inhibition of cell proliferation. Furthermore, functionally blocking Ca 2+ down‐regulated ERK activation and reversed the antiproliferative effect of NO. Both the mitogenic and antimitogenic responses induced by NO were mimicked by a cGMP analogue whereas they were completely antagonized by selective cGMP inhibitors. These results demonstrate for the first time that regulation of cell proliferation by low NO levels is cGMP dependent and occurs via the Ca 2+ /calmodulin/MAP kinase kinase/ERK pathway. In this effect the amplitude of Ca 2+ signalling determines the specificity of the proliferative response to NO possibly by modulating the strength of ERK activation. In contrast to the low level, the high levels (50–300 µ m ) of DETA/NO negatively regulated cell proliferation via a Ca 2+ ‐independent mechanism.