Component of a Polycomb group (PcG) multiprotein PRC1-like complex, a complex class required to maintain the transcriptionally repressive state of many genes, including Hox genes, throughout development. PcG PRC1 complex acts via chromatin remodeling and modification of histones; it mediates monoubiquitination of histone H2A 'Lys-119', rendering chromatin heritably changed in its expressibility. The PRC1-like complex that contains PCGF5, RNF2, CSNK2B, RYBP and AUTS2 has decreased histone H2A ubiquitination activity, due to the phosphorylation of RNF2 by CSNK2B. As a consequence, the complex mediates transcriptional activation (By similarity). In the cytoplasm, plays a role in axon and dendrite elongation and in neuronal migration during embryonic brain development. Promotes reorganization of the actin cytoskeleton, lamellipodia formation and neurite elongation via its interaction with RAC guanine nucleotide exchange factors, which then leads to the activation of RAC1 (PubMed:25533347). Component of a PRC1-like complex that contains PCGF5, RNF2, CSNK2B, RYBP and AUTS2 (PubMed:25519132). Within this complex, interacts directly with PCGF5 and CSNK2B (By similarity). Interacts with the histone acetyltransferase EP300/p300 (By similarity). Interacts (via Pro-rich region) with PREX1, DOCK1 and ELMO2 (PubMed:25533347). Detected both in cytoplasm and nucleus (PubMed:25533347). Colocalizes with RAC1 at actin-rich growth cones (PubMed:25533347). Detected on the promoter region of actively transcribed genes (PubMed:25519132). Detected in brain cortex in embryo, neonates and adults (at protein level) (PubMed:19948250, PubMed:25533347, PubMed:25519132). Detected in embryonic and adult Purkinje cells in the cerebellum (PubMed:19948250). Detected in dorsal thalamus and in dopaminergic neurons in substantia nigra (PubMed:19948250). Detected in embryonic brain cortex at 15 dpc, and at clearly lower levels in adult brain cortex, hippocampus and in cerebellum Purkinje cells (at protein level) (PubMed:25519132). Very low and barely detectable in embryonic brain at 11 dpc. Detected in the developing brain cortex, thalamus and cerebellum at 12 and 14 dpc. Uniformly expressed all along the preplate at 13 dpc. At 16 dpc, highly expressed in neurons in deep and superficial layers of the frontal cortical region of the preplate, with much lower expression in the caudal region or the preplate. Highly expressed in thalamus at 14 dpc, and at much lower levels in adults. Highly expressed in hippocampus after 13 dpc; expression levels increase subsequently and are high in dentate gyrus and the CA region of the hippocampus at 19 dpc. Expression in dentate gyrus, granule cell layer and the CA region of the hippocampus continues in neonates and into adulthood. The Pro-rich region is important for the interaction with RAC guanine nucleotide exchange factors and the subsequent activation of RAC1, which then promotes lamellipodia formation. Brain-specific gene disruption gives rise to no visible phenotype at birth. Mutant mice have normal weight at birth, but then show decreased weight gain over the next few days, decreased milk uptake, impaired motor skills and impaired ultrasonic vocalization after maternal separation. Belongs to the AUTS2 family.