A NHL-domain family protein that functions a translational repressor to inhibit cell proliferation (PubMed:11274060). Plays a central role in translation repression of hb mRNA by being recruited by nos and pum to the Nanos Response Element (NRE), a 16 bp sequence in the hb mRNA 3'-UTR (PubMed:11274060). Probably recruited by other proteins to repress translation of other mRNAs in other tissues (PubMed:11274060). Involved in the regulation of ribosomal RNA synthesis and cell growth (PubMed:11807032). Participates in abdominal segmentation and imaginal disk development (PubMed:11274060). During neuroblast division, segregates asymmetrically and inhibits self-renewal of one of the two daughter cells (PubMed:16564014). Together with the asymmetrically segregating transcription factor prospero ensures that the daughter cell will stop growing, exit the cell cycle, and differentiate into neurons possibly by modulating the function of dm in ganglion mother cells (GMC) (PubMed:11807032, PubMed:16564014). Restricts developmental potential of type II intermediary neuronal progenitor (INP) cells playing a role in proliferation and maturation of the neuroblasts (PubMed:24550111, PubMed:14561773, PubMed:22143802, PubMed:18342578). Interacts with nos and pum (PubMed:11274060). Acts via the formation of a quaternary complex composed of pum, nos, brat and the 3'-UTR mRNA of hb (PubMed:11274060). Not recruited by nos and pum to cyclin B 3'-UTR mRNA (PubMed:11274060). Might interact with mira; the interaction seems to be important for brat localization during mitosis (PubMed:16564014). In embryonic and larval neuroblasts, colocalizes with mira throughout mitosis using it as an adapter to segregate into one of the two daughter cells during asymmetric cell division. Accumulates at the apical cell cortex in prophase, forms a basal crescent in metaphase, and segregates into the ganglion mother cell (GMC). It is cortical in telophase but becomes cytoplasmic in interphase after mira is degraded. Expressed during embryogenesis, mainly in nervous tissues. Expressed in the embryonic central and peripheral nervous systems including the embryonic brain. In third instar larva it is expressed in the larval central nervous system including the brain and the ventral ganglion, in two glands (the ring gland and the salivary gland, and in parts of the foregut) the gastric caeca and the proventriculus. The NHL repeats form six-bladed beta-propeller that mediate the interaction with the pumilio repeats of pum, and are essential for translational effector function. In larval brain, results in deregulated cell cycle and defective differentiation of immature intermediate neuroblast progenitors ultimately leading to overgrowth and proliferation (PubMed:16564014, PubMed:18342578). RNAi-mediated knockdown in the larval brain results in overproliferation of type II neuroblast cells on the dorsal side of the larval brains but had no effect in the type I neuroblast lineage in the ventral nerve cord (PubMed:22143802, PubMed:18342578). Extended N-terminus.