Tribbles homolog 3, also known as Neuronal cell death-inducible putative kinase, p65-interacting inhibitor of NF-kappa-B, SINK and TRIB3, is a Nucleus protein that belongs to the protein kinase superfamily and CAMK Ser/Thr protein kinase family and Tribbles subfamily. Highest expression Of TRIB3 is in liver, pancreas, peripheral blood leukocytes and bone marrow. It is also highly expressed in a number of primary lung, colon and breast tumors. TRIB3 is expressed in spleen, thymus, and prostate and is undetectable in other examined tissues, including testis, ovary, small intestine, colon, leukocyte, heart, brain, placenta, lung, skeletal muscle, and kidney. TRIB3 disrupts insulin signaling by binding directly to Akt kinases and blocking their activation. TRIB3 may bind directly to and mask the 'Thr-38' phosphorylation site in AKT1. It binds to ATF4 and inhibits its transcriptional activation activity. TRIB3 interacts with the NF-kappa-B transactivator p65 RELA and inhibits its phosphorylation and thus its transcriptional activation activity. It interacts with MAPK kinases and regulates activation of MAP kinases. It may play a role in programmed neuronal cell death but does not appear to affect non-neuronal cells. TRIB3 does not display kinase activity.