Phosphorylation of the transcription factor Sp4 is reduced by NMDA receptor signaling.

Abstract

The regulation of transcription factor function in response to neuronal activity is important for development and function of the nervous system. The transcription factor Sp4 regulates the developmental patterning of dendrites, contributes to complex processes including learning and memory, and has been linked to psychiatric disorders such as schizophrenia and bipolar disorder. Despite its many roles in the nervous system, the molecular mechanisms regulating Sp4 activity are poorly understood. Here, we report a site of phosphorylation on Sp4 at serine 770 that is decreased in response to membrane depolarization. Inhibition of the voltage-dependent NMDA receptor increased Sp4 phosphorylation. Conversely, stimulation with NMDA reduced the levels of Sp4 phosphorylation, and this was dependent on the protein phosphatase 1/2A. A phosphomimetic substitution at S770 impaired the Sp4-dependent maturation of cerebellar granule neuron primary dendrites, whereas a non-phosphorylatable Sp4 mutant behaved like wild type. These data reveal that transcription factor Sp4 is regulated by NMDA receptor-dependent activation of a protein phosphatase 1/2A signaling pathway. Our findings also suggest that the regulated control of Sp4 activity is an important mechanism governing the developmental patterning of dendrites.

• Authors: Gregory Saia, Jasmin Lalonde, Xinxin Sun, Belén Ramos, Grace Gill
• Journal: Journal of neurochemistry (J Neurochem) Vol. 129 Issue 4 Pg. 743-52 (May 2014) ISSN: 1471-4159 [Electronic] England
• PMID: 24475768 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: © 2014 International Society for Neurochemistry.

Chemical References

• Calcineurin Inhibitors
• Calcium Channels
• RNA, Small Interfering
• Receptors, N-Methyl-D-Aspartate
• Recombinant Fusion Proteins
• Sp4 Transcription Factor
• Sp4 protein, rat
• Okadaic Acid
• N-Methylaspartate
• Potassium Chloride
• Dizocilpine Maleate
• Calcineurin
• Protein Phosphatase 1
• Protein Phosphatase 2

Topics

• Animals
• Calcineurin (physiology)
• Calcineurin Inhibitors
• Calcium Channels (physiology)
• Cell Line
• Cerebellum (cytology)
• Dendrites (ultrastructure)
• Dizocilpine Maleate (pharmacology)
• Humans
• Membrane Potentials (drug effects)
• Mutagenesis, Site-Directed
• N-Methylaspartate (pharmacology)
• Neurogenesis
• Neurons (drug effects, metabolism, ultrastructure)
• Okadaic Acid (pharmacology)
• Point Mutation
• Potassium Chloride (pharmacology)
• Protein Phosphatase 1 (antagonists & inhibitors, physiology)
• Protein Phosphatase 2 (physiology)
• Protein Processing, Post-Translational
• RNA, Small Interfering (pharmacology)
• Rats
• Receptors, N-Methyl-D-Aspartate (drug effects, physiology)
• Recombinant Fusion Proteins (metabolism)
• Signal Transduction (physiology)
• Sp4 Transcription Factor (chemistry, metabolism)
• Transfection