Transcription factor, which is required in the single sleep-active ring interneuron RIS for sleep-like behavioral quiescence induced by neuropeptide signaling in larvae (PubMed:24184105, PubMed:26949257). Regulates gene expression of sleep-inducing FMRFamide-like neuropeptide flp-11 in RIS (PubMed:26949257). Binds DNA as a dimer. Expressed in five interneurons AIB, RIB and RIS. Expressed strongly during late embryogenesis and early larval development in three types of interneurons, the paired neurons AIB and RIB and the unpaired neuron RIS in the head, with the strongest expression in RIS. Expression after embryonic development decreases until the adult stage. Regulates its own expression during larval development (PubMed:24184105). Transcriptionally regulated by transcription factor lim-6 in RIS interneuron in all developmental stages (PubMed:26949257). Animals develop with normal speed and go normally through the molt. They stop feeding for a normal time before each molt, but average nose speed is reduced by only about 10% and unlike wild-type, they are never immobile. The command interneurons AVA and AVE, which control backward movement, are not shut down during sleep-like behavior. Optogenetic channelrhodopsin activation of AIBs, RIBs and RIS interneurons during wake-like behavior using blue light does not trigger acute immobility and cessation of pumping in L1 larvae, instead it causes an increase in mobility (PubMed:24184105). No change in GABAergic function of neurons as unc-25 and the vesicular GABA transporter gene unc-47 are expressed normally. The expression of a neuropeptide gene flp-11 is strongly down-regulated in pretzel-stage embryos and in sleeping L4 larvae (PubMed:26949257). Belongs to the AP-2 family.