Phosphorylates 'Ser-10' of histone H3. May regulate gene expression by establishing or maintaining the structure of more open chromatin regions. Also required for normal polytene chromosome structure, for oogenesis and for viability throughout development. Regulates the structure of polytene chromosomes in salivary glands. May phosphorylate 'Ser-1' of histone H2A. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Interacts with lola. Interacts with proteins of the male specific lethal (MSL) dosage compensation complex; this interaction is mediated by the kinase domains. Associates with chromosomes throughout the cell cycle. Localizes to interband regions along the polytene chromosomes and is enriched almost two-fold on the male X chromosome compared to the autosome. Autophosphorylated in vitro. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.