A screen for modulators of N-end rule pathway

Arginyl‐tRNA‐protein transferase (ATE1) is responsible for the posttranslational transfer of arginine onto proteins bearing N‐terminal acidic amino acids. The N‐end rule pathway of the ubiquitin proteasome system recognizes proteins bearing N‐terminal hydrophobic or basic amino acids such as arginine. These Nterminal amino acids function as degradation signals called Ndegrons. We discovered that ATE1 is required for the degradation of TDP43247, a specific fragment of the human TDP43 protein associated with Amyotrophic Lateral Sclerosis and other forms of dementia. Here, we generated a fluorescent GFP reporter bearing the N‐degron of TDP43247 (247‐ DLIIKGISVHISNAEPK‐263) which elicits a “digital response” with respect to degradation by the N‐ end rule pathway. Using this reporter, we are developing a highly sensitive, cell‐based screen to identify chemical or genetic modifiers of the N‐end rule pathway. Ultimately, this work may offer therapeutic potential in treating neurodegeneration.