Serine / threonine-protein kinase tousled-like 2, also known as PKU-alpha, Tousled-like kinase 2 and TLK2, is a nucleus protein which belongs to the protein kinase superfamily and Ser/Thr protein kinase family. The tousled-like kinases are an evolutionarily conserved family of proteins implicated in DNA repair, DNA replication and mitosis in metazoans and plants. Their absence from the yeasts and other eukaryotic 'microbes' suggests a specific role for them in the development of multicellular organisms. Tousled-like kinase 2 / TLK2 is widely expressed. It is present in fetal placenta, liver, kidney, pancreas, heart and skeletal muscle. It is also found in adult cell lines. Tousled-like kinase 2 / TLK2 contains one protein kinase domain. Tousled-like kinase 2 / TLK2 is rapidly and transiently inhibited by phosphorylation following the generation of DNA double-stranded breaks during S-phase. This is cell cycle checkpoint and ATM-pathway dependent and appears to regulate processes involved in chromatin assembly.