Nascent Polypeptide Associated Complex Alpha 2 (NACa2)

By screening an epithelial cell line cDNA expression library using a cDNA encoding an IgE-reactive C-terminal fragment of NACA, Mossabeb et al. (2002) cloned a novel NACA isoform they called 'Hom s 2.01.' NACA protein is specifically expressed in bone during development and acts as a transcriptional coactivator in conjunction with acidic activators.

Nascent Polypeptide Associated Complex Alpha 2 has a calculated molecular mass of 23.2 kD and contains 215 amino acids, 21 of which differ from NACA. It consists mostly of alpha helices and a single beta sheet and contains 2 N-glycosylation sites and several sites for protein phosphorylation. Mossabeb et al. (2002) showed that the recombinant full-length NACA isoform cloned by them bound IgE autoantibodies.