RNA-binding protein that functions as regulator of alternative splicing for multiple target mRNAs, including PTPRC/CD45 and STAT5A. Required for alternative splicing of PTPRC. Interacts with HNRNPL. Up-regulated in stimulated T-cells. Widely expressed. Detected in bone marrow stroma cells, skeletal muscle, heart, placenta, pancreas, kidney and lung. 4 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.