Involved in many cell functions, including pre-mRNA splicing, the aryl hydrocarbon receptor (AHR) pathway, F-actin organization and protein ubiquitination. Plays a role in the dynamic organization of the actin skeleton as a stabilizer of actin filaments by association with F-actin through Kelch repeats (By similarity). Protects cells from cell death induced by actin destabilization (By similarity). Functions as modifier of the AHR/Aryl hydrocarbon receptor pathway increasing the concentration of AHR available to activate transcription (PubMed:16582008). In addition, functions as a negative regulator of BCR(KLHL20) E3 ubiquitin ligase complex to prevent ubiquitin-mediated proteolysis of PML and DAPK1, two tumor suppressors (PubMed:25619834). Inhibits pre-mRNA splicing (in vitro) (PubMed:9696811). (Microbial infection) Involved in the alternative splicing of influenza A virus M1 mRNA through interaction with HNRNPK, thereby facilitating the generation of viral M2 protein. Homodimer; through the BTB domain (By similarity). Interacts with AHR/Aryl hydrocarbon receptor (PubMed:16582008). Interacts with HNRNPK (PubMed:23825951). Interacts (via kelch repeats) with KLHL20 (via kelch repeats); this interaction blocks the assembly of Cul3-KLHL20 complex (PubMed:25619834). (Microbial infection) Interacts with influenza A virus non-structural protein 1/NS (PubMed:9696811). Associated with actin filaments (By similarity). Localization related to speckle domains which correspond to interchromatin granules and are enriched in factors involved in pre-mRNA splicing (PubMed:9696811). Following influenza A virus infection, redistribution from speckles to a more diffuse distribution in the nucleoplasm (PubMed:9696811). When the BTB domain is lacking, AHR signaling induction promoted by IVNS1ABP is massively increased; Thus, the BTB domain inhibits AHR signaling induced by IVNS1ABP. The disease may be caused by variants affecting the gene represented in this entry.