The function of NOTCH2NLB (notch 2 N-terminal like B, Ensembl gene identifier ENSG00000286019) is as follows. Human-specific protein that promotes neural progenitor proliferation and evolutionary expansion of the brain neocortex by regulating the Notch signaling pathway (PubMed:29561261, PubMed:29856954, PubMed:29856955). Able to promote neural progenitor self-renewal, possibly by down-regulating neuronal differentiation genes, thereby delaying the differentiation of neuronal progenitors and leading to an overall final increase in neuronal production (PubMed:29856954, PubMed:29856955). Acts by enhancing the Notch signaling pathway via two different mechanisms that probably work in parallel to reach the same effect (PubMed:29856954, PubMed:29856955). Enhances Notch signaling pathway in a non-cell-autonomous manner via direct interaction with NOTCH2 (PubMed:29856954). Also promotes Notch signaling pathway in a cell-autonomous manner through inhibition of cis DLL1-NOTCH2 interactions, which promotes neuronal differentiation (PubMed:29856955). {ECO:0000269|PubMed:29561261, ECO:0000269|PubMed:29856954, ECO:0000269|PubMed:29856955}.