Technical Abstract: We have previously demonstrated that smoke exposure and/or high dose beta-carotene supplementation decrease levels of retinoic acid and retinoic acid receptor beta (RAR-beta) protein, but increase levels of c-Jun and proliferating cellular nuclear antigen protein in the lungs of ferrets. In contrast, low dose beta-carotene can prevent the decreased lung retinoic acid and the smoke-induced lung lesions. In the present study, we further investigated whether smoke exposure and/or beta-carotene supplementation could affect Jun N-terminal kinase (JNK), p38 MAPK, and p53 in the lungs of ferrets. Ferrets were subjected to either a high or low dose of beta-carotene and cigarette smoke exposure for 6 months. There were greater protein levels of phosphorylated JNK, p38, and c-Jun, but lower levels of mitogen-activated kinase phophatase-1 (MKP-1) in groups exposed to smoke and/or high dose beta-carotene. Both phosphorylated p53 and total p53 were substantially increased in the lungs of these groups. In contrast, low dose beta-carotene greatly attenuated the smoke-induced phosphorylation of JNK, p38, c-Jun, p53, and total p53, accompanied by up-regulated MKP-1. Smoke exposure increased mitogen-activated protein kinase kinase-4 phosphorylation regardless of beta-carotene supplementation. These data indicate that restoration of retinoic acid and MKP-1 by low dose beta-carotene in the lungs of ferrets can prevent the smoke-enhanced phosphorylation of JNK, p38, and p53.