The growing role of mTOR in neuronal development and plasticity.

Neuronal development and synaptic plasticity are highly regulated processes in which protein kinases play a key role. Recently, increasing attention has been paid to a serine/threonine protein kinase called mammalian target of rapamycin (mTOR) that has well-known functions in cell proliferation and growth. In neuronal cells, mTOR is implicated in multiple processes, including transcription, ubiquitin-dependent proteolysis, and microtubule and actin dynamics, all of which are crucial for neuronal development and long-term modification of synaptic strength. The aim of this article is to present our current understanding of mTOR functions in axon guidance, dendritic tree development, formation of dendritic spines, and in several forms of long-term synaptic plasticity. We also aim to present explanation for the mTOR effects on neurons at the level of mTORregulated genes and proteins.