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Nerve growth factor increases connexin43 phosphorylation and gap junctional intercellular communication
Author(s) -
Cushing Paul,
Bhalla Ruchi,
Johnson Andrew M.,
Rushlow Walter J.,
Meakin Susan O.,
Belliveau Daniel J.
Publication year - 2005
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.20689
Subject(s) - connexin , microbiology and biotechnology , phosphorylation , gap junction , nerve growth factor , mapk/erk pathway , fluorescence recovery after photobleaching , neurotrophin , biology , tropomyosin receptor kinase a , protein kinase a , signal transduction , neurotrophic factors , intracellular , chemistry , biochemistry , receptor , membrane
The function of gap junctions is regulated by the phosphorylation state of their connexin subunits. Numerous growth factors are known to regulate connexin phosphorylation; however, the effect of nerve growth factor on gap junction function is not understood. The phosphorylation of connexin subunits is a key event during many aspects of the lifecycle of a connexin, including open/close states, assembly/trafficking, and degradation, and thus affects the functionality of the channel. PC12 cells infected with connexin43 (Cx43) retrovirus were used as a neuronal model to characterize the signal transduction pathways activated by nerve growth factor (NGF) that potentially affect the functional state of Cx43. Immunoblot analysis demonstrated that Cx43 and the mitogen‐activated protein kinase (MAPK), ERK‐1/2, were phosphorylated in response to TrkA activation via NGF and that phosphorylation could be prevented by treatment with the MEK‐1/2 inhibitor U0126. The effects of NGF on gap junction intercellular communication were examined by monitoring fluorescence recovery after photobleaching PC12‐Cx43 cells preloaded with calcein. Fluorescence recovery in the photobleached area increased after NGF treatment and decreased when pretreated with the MEK‐1/2 inhibitor U0126. These data are the first to show a direct signaling link between neurotrophins and the phosphorylation of connexin proteins through the MAPK pathway resulting in increased gap junctional intercellular communication. Neurotrophic regulation of connexin activity provides a novel mechanism of regulating intercellular communication between neurons during nervous system development and repair. © 2005 Wiley‐Liss, Inc.