Harnessing the master transcriptional repressor REST to reciprocally regulate neurogenesis.

Neurogenesis begins in embryonic development and continues at a reduced rate into adulthood in vertebrate species, yet the signaling cascades regulating this process remain poorly understood. Plasma membrane-initiated signaling cascades regulate neurogenesis via downstream pathways including components of the transcriptional machinery. A nuclear factor that temporally regulates neurogenesis by repressing neuronal differentiation is the repressor element 1 (RE1) silencing transcription (REST) factor. We have recently discovered a regulatory site on REST that serves as a molecular switch for neuronal differentiation. Specifically, C-terminal domain small phosphatase 1, CTDSP1, present in non-neuronal cells, maintains REST activity by dephosphorylating this site. Reciprocally, extracellular signal-regulated kinase, ERK, activated by growth factor signaling in neural progenitors, and peptidylprolyl cis/trans isomerase Pin1, decrease REST activity through phosphorylation-dependent degradation. Our findings further resolve the mechanism for temporal regulation of REST and terminal neuronal differentiation. They also provide new potential therapeutic targets to enhance neuronal regeneration after injury.