InterPro domain: IPR045117

Ataxin-2 has many functions, such as endocytic receptor cycling [ 1 ], translational regulation, embryonic development [ 2 ], energy metabolism and weight regulation [ 3 ]. Mutations of the Ataxin-2 gene cause spinocerebellar ataxia 2 (SCA2), a neurodegenerative disorder leading to predominant loss of Purkinje cells in the cerebellum and impairment of motor coordination [ 4 ]. In SCA2, expansion of a CAG repeat in exon 1 of the Ataxin-2 (ATXN2) gene causes expansion of a polyQ domain in the ATXN2 protein [ 5 ]. ATXN2 has been shown to interact with many proteins. It interacts with multiple RNA-binding proteins (RBPs), staufen, IP3R, RGS8 mRNA, endophilins and CIN85 [ 6 ].

This entry represents a group of RNA-binding proteins , including Ataxin-2 from animals, Pbp1 from fungi and Cid3/4 from Arabidopsis.Pbp1 interacts with Pab1 to regulate mRNA polyadenylation [ 7 , 8 ]. It promotes mating-type switching in mother cells by positively regulating HO mRNA translation [ 9 ] and forms a condensate in response to respiratory status to regulate TORC1 signalling [ 10 ]. It is also involved in P-body-dependent granule assembly [ 11 ].Cid3/4 may have a role in developmental pathways throughout the life cycle of plants [ 12 ].

1. Ataxin-2 associates with the endocytosis complex and affects EGF receptor trafficking. Cell. Signal. 20, 1725-39
2. ATX-2, the C. elegans ortholog of ataxin 2, functions in translational regulation in the germline. Development 131, 4831-41
3. Generation and characterization of Sca2 (ataxin-2) knockout mice. Biochem. Biophys. Res. Commun. 339, 17-24
4. Moderate expansion of a normally biallelic trinucleotide repeat in spinocerebellar ataxia type 2. Nat. Genet. 14, 269-76
5. Ataxin-2 regulates RGS8 translation in a new BAC-SCA2 transgenic mouse model. PLoS Genet. 11, e1005182
6. Spinocerebellar Ataxia Type 2. Adv. Exp. Med. Biol. 1049, 175-195
7. Identification of factors regulating poly(A) tail synthesis and maturation. Mol. Cell. Biol. 24, 4196-206
8. Pbp1p, a factor interacting with Saccharomyces cerevisiae poly(A)-binding protein, regulates polyadenylation. Mol. Cell. Biol. 18, 7383-96
9. Posttranscriptional regulation of HO expression by the Mkt1-Pbp1 complex. Mol. Cell. Biol. 24, 3670-81
10. Yeast Ataxin-2 Forms an Intracellular Condensate Required for the Inhibition of TORC1 Signaling during Respiratory Growth. Cell 177, 697-710.e17
11. P bodies promote stress granule assembly in Saccharomyces cerevisiae. J. Cell Biol. 183, 441-55
12. The ATXN2 Orthologs CID3 and CID4, Act Redundantly to In-Fluence Developmental Pathways throughout the Life Cycle of Arabidopsis thaliana. Int J Mol Sci 22