CDK11A is a cyclin-dependent kinase with dual roles in cell cycle regulation and RNA processing. The protein exists as multiple isoforms with cell-cycle-specific expression, particularly during G2-M phases 1. CDK11A functions as an RNA polymerase II CTD kinase, phosphorylating serine-2 residues on POLR2A to regulate transcription initiation and elongation 2. Beyond transcription, CDK11A plays a critical role in spliceosome regulation by phosphorylating the core component SF3B1, with its activation dependent on CDK7-mediated phosphorylation of threonine 595 3. During mitosis, CDK11A promotes centromeric transcription essential for maintaining centromeric cohesion 4. CDK11A also regulates selective autophagy, specifically ER-phagy, independent of bulk autophagy pathways 5. In cancer biology, CDK11A phosphorylates mitoribosomal protein MRPS23, affecting breast cancer cell proliferation and survival through PI3K-AKT and antiapoptotic pathways 6. CDK11A expression is frequently dysregulated in breast cancer with prognostic significance for overall and relapse-free survival 7. The CDK11A gene itself is subject to complex transcriptional regulation involving Ets-1 and CREB transcription factors 89, with gene deletion on chromosome 1 associated with tumor development.