ATXN2 is a polyglutamine (polyQ) protein with key roles in RNA metabolism, stress response, calcium regulation, and circadian rhythm. It is involved in several neurodegenerative diseases, including spinocerebellar ataxia type 2 (SCA2), amyotrophic lateral sclerosis (ALS), and Parkinson's disease. The ATXN2 gene contains a CAG repeat sequence that encodes a polyQ tract. When this tract is expanded, it leads to conformational changes that cause toxic gain or loss of function, contributing to neurodegeneration. SCA2 is the most well-characterized disease associated with ATXN2, but intermediate expansions are also implicated in ALS and Parkinsonism. SCA2 is an incurable disease with no known cure, and patients rely on symptomatic treatments. The mechanisms underlying SCA2 pathogenesis include protein aggregation, autophagy impairment, RNA-mediated toxicity, oxidative stress, and calcium homeostasis disruption. ATXN2 is involved in various cellular processes, including RNA metabolism, translation, endocytosis, and calcium signaling. It also plays a role in the formation and dynamics of stress granules. ATXN2 interacts with several proteins, including TDP-43, and its dysfunction can lead to neuronal inclusions and neurodegeneration. The expanded ATXN2 protein is associated with the formation of insoluble aggregates that contribute to neuronal death. Additionally, ATXN2 is involved in the regulation of the circadian rhythm and metabolism. In other diseases, such as ALS and Parkinson's disease, ATXN2 may also play a role, although the exact mechanisms are not fully understood. The study of ATXN2 and its involvement in disease is an active area of research, with the aim of developing new therapeutic strategies.ATXN2 is a polyglutamine (polyQ) protein with key roles in RNA metabolism, stress response, calcium regulation, and circadian rhythm. It is involved in several neurodegenerative diseases, including spinocerebellar ataxia type 2 (SCA2), amyotrophic lateral sclerosis (ALS), and Parkinson's disease. The ATXN2 gene contains a CAG repeat sequence that encodes a polyQ tract. When this tract is expanded, it leads to conformational changes that cause toxic gain or loss of function, contributing to neurodegeneration. SCA2 is the most well-characterized disease associated with ATXN2, but intermediate expansions are also implicated in ALS and Parkinsonism. SCA2 is an incurable disease with no known cure, and patients rely on symptomatic treatments. The mechanisms underlying SCA2 pathogenesis include protein aggregation, autophagy impairment, RNA-mediated toxicity, oxidative stress, and calcium homeostasis disruption. ATXN2 is involved in various cellular processes, including RNA metabolism, translation, endocytosis, and calcium signaling. It also plays a role in the formation and dynamics of stress granules. ATXN2 interacts with several proteins, including TDP-43, and its dysfunction can lead to neuronal inclusions and neurodegeneration. The expanded ATXN2 protein is associated with the formation of insoluble aggregates that contribute to neuronal death. Additionally, ATXN2 is involved in the regulation of the circadian rhythm and metabolism. In other diseases, such as ALS and Parkinson's disease, ATXN2 may also play a role, although the exact mechanisms are not fully understood. The study of ATXN2 and its involvement in disease is an active area of research, with the aim of developing new therapeutic strategies.