Probable transcription factor that regulates neuronal differention, including synapse assembly of the cholinergic motor neuron M4 (PubMed:24690231, PubMed:25474681). Activates expression of growth factor, neuropeptide and transcription factor genes, such as TGF-beta dbl-1, FMRFamide-like flp-5 and transcription repressor zag-1, in the M4 neuron (PubMed:24690231, PubMed:25474681). Required for pharynx peristalsis (PubMed:18161854). Expressed from 172 minutes after the first cleavage, in the ABalaappa cell and continuing in its daughters, and in the cholinergic motor neuron M4 from mid-embryogenesis through to adult stages. Reduced pharynx pumping rate and abnormal isthmus peristalses in L1 stage larvae (PubMed:18161854). Feeding defects, characterized by a stuffed pharynx, as a result of ingested E.coli packing the lumen of the corpus and anterior isthmus in L4 stage larvae (PubMed:18161854). Defects in pharyngeal g1 gland cell morphology (PubMed:24690231). Reduced expression of TGF-beta, dbl-1, in the cholinergic motor neuron M4, but normal expression of other markers of differentiation, such as serotonin receptor ser-7b and the vesicular acetylcholine transporter unc-17 (PubMed:18161854). Belongs to the NK-2 homeobox family.