Syntrophin-associated serine/threonine kinase-124 (SAST124) is a signalling molecule belonging to the microtubule-associated serine/threonine kinases. They have a unique structural feature with a serine/threonine kinase domain and a postsynaptic density protein-95/discs large/zona occludens-1 domain. SAST124 binds syntrophin, an adaptor protein that connects siganlling molecules to the dystrophin-associated protein complex. It has a role in transcriptional regulation in some cells and may have other functions in other cell types.