DEVELOPMENTAL NEUROSCIENCEActivation of c-Jun N-terminal kinase is required for neurite outgrowth of dopaminergic neuronal cellsEom, Dae-Seok*; Choi, Won-Seok*; Ji, Suena; Cho, Jin W.CA; Oh, Young J.CAAuthor Information Department of Biology, Yonsei University College of Science, Seoul 120-749, Korea *These authors contributed equally to this work. CACorresponding Author: email@example.com and firstname.lastname@example.org Received 3 April 2005; accepted 6 April 2005 NeuroReport: May 31st, 2005 - Volume 16 - Issue 8 - p 823-828 Buy SDC Abstract Recent studies indicate that activation of stress-activated protein kinases may be implicated in a broad range of biological activities including differentiation. To directly examine whether stress-activated protein kinases are involved in neuronal differentiation, we utilized retinoic acid-induced and spontaneous models of neurite outgrowth in dopaminergic neurons. Here, we show that retinoic acid-induced neurite outgrowth in MN9D dopaminergic neuronal cells was accompanied by activation of c-Jun N-terminal kinase but not p38. Consequently, cotreatment with a specific inhibitor of c-Jun N-terminal kinase or overexpression of c-Jun N-terminal kinase-binding domain of c-Jun N-terminal kinase-interacting protein-1 blocked retinoic acid-induced neurite outgrowth. In primary cultures of dopaminergic neurons, the extent of neurite outgrowth increased spontaneously in a time-dependent manner. When these cultures were treated with a specific inhibitor of c-Jun N-terminal kinase, the total extent of neurites, the primary neurite length and the number of neurites per cell were suppressed significantly. Thus, our data indicate that the c-Jun N-terminal kinase signal seems to play an important role during morphological differentiation in cultured dopaminergic neurons. © 2005 Lippincott Williams & Wilkins, Inc.