In the cyanobacterium Synechococcus PCC 7942 (Swiss:P35087) , nblA triggers degradation of light-harvesting phycobiliproteins in response to deprivation nutrients including nitrogen, phosphorus and sulphur. The mechanism of nblA function is not known, but it has been hypothesised that nblA may act by disrupting phycobilisome structure, activating a protease or tagging phycobiliproteins for proteolysis. Members of this family have also been identified in the chloroplasts of some red algae.

1: Convergence of two global transcriptional regulators on nitrogen induction of the stress-acclimation gene nblA in the cyanobacterium Synechococcus sp. PCC 7942. Luque I, Zabulon G, Contreras A, Houmard J; Mol Microbiol 2001;41:937-947. PMID:11532155