ATXN1L encodes the Ataxin 1-Like protein. Both Ataxin 1 and Ataxin 1-Like protein function as chromatin-binding factors that repress Notch signaling in the absence of Notch activation. The ATXN1L protein is also believed to be involved in extracellular matrix organization, hematopoietic stem cell proliferation and lung alveolus development.

As the protein is yet to be fully characterized, studies of the mouse orthologue Atxn1l have helped elucidate its physiological role. Analysis of knock-in mouse models of Spinocerebellar Ataxia 1 (SCA1) has revealed that elevated Atxn1l levels suppress mutant Atxn1 cytotoxicity. 

The ATXN1L gene, located on the long arm of chromosome 16, spans a length of 39.2 kb of DNA. Its coding sequence is spread across 3 exons and it encodes a 73.3 kDa protein product consisting of 689 amino acids. The gene is expressed in several regions of the brain, particularly the cerebellum and cerebral cortex.