Failure of damaged axons to regenerate and reestablish functional circuitry is the primary cause that results in permanent disabilities after central nervous system (CNS) injury, and is also a major factor contributing to the non-reversible neurologic dysfunction seen in neurodegenerative diseases. Of approximately 1.9% of the U.S. population with paralysis, some 1,275,000 are paralyzed as the result of a spinal cord injury (SCI). SCIs frequently result in at least some incurable impairment even with the best possible treatment and patients with complete injuries recover very little lost function. Under pathological situations such as multiple sclerosis, the second most common neurological disorder leading to disability in young adults, failure of damaged axons to regenerate contributes to neurologic abnormalities. Despite ample efforts in the past few decades, which have led to the discoveries of extracellular factors that impede, and intrinsic pathways in mature neurons that diminish the regenerative capacity of axons, effective therapies have not emerged given the fact that simply removing those inhibitory cues confers limited regrowth and that our understanding of neurons’ intrinsic regenerative properties still remains incomplete, indicating that additional regulatory machinery must be in place. This highlights the urgent need to identify novel molecular targets for therapy. With the goal to find novel factors essential for CNS axon regeneration, we have utilized a Drosophila sensory neuron injury model that resembles mammalian injury at the phenotypical and molecular level in a candidate- based genetic screen, and identified the Piezo-Atr (Ataxia telangiectasia and Rad3 related) pathway as inhibitors for axon regeneration. This proposal aims to determine the cellular and molecular mechanisms underlying Piezo- Atr’s function in flies and to elucidate the role of the mammalian Atr after peripheral or spinal cord injury. Atr is an essential component of the DNA damage response and also responds to mechanical force. This pathway has never been implicated in axon regeneration, and our study will thus provide exciting insights into the potential links among axon injury, DNA damage response, mechanosensation and regeneration, and will open new avenues of research for regeneration and spinal cord injury. Taking advantage of the power of fly genetics to identify novel factors and the mammalian injury model, this strategy offers a unique opportunity to gain insights into the repertoire of regeneration regulators, which may drive novel treatments to promote recovery in patients with neural injury or neurodegenerative diseases.