Mediation of NGF signaling by post-translational inhibition of HES-1, a basic helix-loop-helix repressor of neuronal differentiation.
The induction of neurite outgrowth by NGF is a transcription-dependent process in PC12 cells, but the transcription factors that mediate this process are not known. Here we show that the bHLH transcriptional repressor HES-1 is a mediator of this process. Inactivation of endogenous HES-1 by forced expression of a dominant-negative protein induces neurite outgrowth in the absence of NGF and increases response to NGF. In contrast, expression of additional wild-type HES-1 protein represses and delays response to NGF. Endogenous HES-1 DNA-binding activity is post-translationally inhibited during NGF signaling in vivo, and phosphorylation of PKC consensus sites in the HES-1 DNA-binding domain inhibits DNA binding by purified HES-1 in vitro. Mutation of these sites generates a constitutively active protein that strongly and persistently blocks response to NGF. These results suggest that post-translational inhibition of HES-1 is both essential for and partially mediates the induction of neurite outgrowth by NGF signaling.
Ström
A
A
Department of Cell Biology and Anatomy, Cornell University Medical College, New York, New York 10021, USA.
Castella
P
P
Rockwood
J
J
Wagner
J
J
Caudy
M
M
D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D002454:Cell Differentiation / Q000502:physiology; D004247:DNA / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression; D006131:Growth Inhibitors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D018257:Helix-Loop-Helix Motifs; D018398:Homeodomain Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D007211:Indoles / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D051379:Mice; D009414:Nerve Growth Factors / Q000378:metabolism*; D016501:Neurites; D009474:Neurons / Q000166:cytology* / Q000187:drug effects; D016716:PC12 Cells; D010766:Phosphorylation; D014176:Protein Biosynthesis; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D012097:Repressor Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D012694:Serine / Q000378:metabolism; D015398:Signal Transduction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D000072056:Transcription Factor HES-1
D051792:Basic Helix-Loop-Helix Proteins; D004247:DNA; D004791:Enzyme Inhibitors; D006131:Growth Inhibitors; D018398:Homeodomain Proteins; D007211:Indoles; D008301:Maleimides; D009414:Nerve Growth Factors; D011493:Protein Kinase C; D012097:Repressor Proteins; D012694:Serine; D013755:Tetradecanoylphorbol Acetate; D000072056:Transcription Factor HES-1; C489734:Hes1 protein, mouse; C489735:Hes1 protein, rat; C088060:bisindolylmaleimide