RNA-binding protein that plays a role in the regulation of alternative splicing and influences mRNA splice site selection and exon inclusion (By similarity). Binds both poly(A) and poly(U) homopolymers. Phosphorylation by PTK6 inhibits its RNA-binding ability. Induces an increased concentration-dependent incorporation of exon in CD44 pre-mRNA by direct binding to purine-rich exonic enhancer (By similarity). Can regulate alternative splicing of neurexins NRXN1-3 in the laminin G-like domain 6 containing the evolutionary conserved neurexin alternative spliced segment 4 (AS4) involved in neurexin selective targeting to postsynaptic partners. Regulates cell-type specific alternative splicing of NRXN1 at AS4 and acts synergystically with SAM68 in exon skipping. In contrast acts antagonistically with SAM68 in NRXN3 exon skipping at AS4 (PubMed:22196734, PubMed:24469635). Its phosphorylation by FYN inhibits its ability to regulate splice site selection (By similarity). May function as an adapter protein for Src kinases during mitosis (PubMed:10077576). Self-associates to form homooligomers (By similarity). Interacts with KHDRBS1/SAM68; heterooligomer formation of KHDRBS family proteins may modulate RNA substrate specificity (PubMed:10077576). Interacts with RBMX, SAFB, SFRS9 and YTHDC1 (By similarity). Interacts with FYN and PLCG1 (via SH3 domain). Interacts (phosphorylated) with FYN, GRB2, PLCG1 and RASA1 (via SH2 domain) (PubMed:10077576). Expressed in heart, skin, brain, colon, spleen, kidney, cervix and testis. In adult cerebellum expressed predominantly in Purkinje cells and in the hippocampus is abundantly expressed in glutamatergic dentate granule cells and in specific inhibitory Schaffer collateral-associated and path-associated interneurons; expression is restricted to neuronal subpopulations largely non-overlapping with expression of KHDRBS3/SLM-2 (at protein level). In the developing cerebellum expression is increasing in the first 3 postnatal weeks. Methylated. Tyrosine phosphorylated by FYN, PTK6 and SRC. Tyrosine phosphorylated by SRC during mitosis. Belongs to the KHDRBS family.