Triad of TDP43 control in neurodegeneration: autoregulation, localization and aggregation.

TLDR: Tziortzouda, Van Den Bosch and Hirth as discussed by the authors described three intrinsic mechanisms that control TARDBP levels and localization and are altered to drive pathology, including autoregulation, nucleocytoplasmic transport and phase transition.

Abstract: Cytoplasmic aggregation of TAR DNA-binding protein 43 (TDP43; also known as TARDBP or TDP-43) is a key pathological feature of several neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). TDP43 typically resides in the nucleus but can shuttle between the nucleus and the cytoplasm to exert its multiple functions, which include regulation of the splicing, trafficking and stabilization of RNA. Cytoplasmic mislocalization and nuclear loss of TDP43 have both been associated with ALS and FTD, suggesting that calibrated levels and correct localization of TDP43 — achieved through an autoregulatory loop and tightly controlled nucleocytoplasmic transport — safeguard its normal function. Furthermore, TDP43 can undergo phase transitions, including its dispersion into liquid droplets and its accumulation into irreversible cytoplasmic aggregates. Thus, autoregulation, nucleocytoplasmic transport and phase transition are all part of an intrinsic control system regulating the physiological levels and localization of TDP43, and together are essential for the cellular homeostasis that is affected in neurodegenerative disease. Accumulation of TAR DNA-binding protein 43 (TDP43) in the neuronal cytoplasm and its loss from the nucleus are characteristic features of several neurodegenerative diseases. Tziortzouda, Van Den Bosch and Hirth describe three intrinsic mechanisms that control TDP43 levels and localization and are altered to drive pathology.