NEUROCHEMISTRYZinc induces neurofilament phosphorylation independent of p70 S6 kinase in N2a cellsBjörkdahl, Cecilia; Sjögren, Magnus J; Winblad, Bengt; Pei, Jin-JingCA Author Information Division of Experimental Geriatrics, Department of Neurotec, Karolinska Institutet, S-141 86 Huddinge, Sweden CACorresponding author: [email protected] Received 9 February 2005; accepted 16 February 2005 NeuroReport: April 25, 2005 - Volume 16 - Issue 6 - p 591-595 Buy Abstract Hyperphosphorylated neurofilaments are a part of neurofibrillary tangles in Alzheimer's disease brains. Zinc has been shown to be increased in the brain areas heavily affected by Alzheimer pathologies. Zinc could induce tau hyperphosphorylation in SH-SY5Y and N2a cells, and tau phosphorylation may be mediated by p70 S6 kinase activation. Many of the tau kinases can also phosphorylate neurofilaments, and in this study we wanted to see whether neurofilament phosphorylation is regulated by p70 S6 kinase in N2a cells. We found that zinc induces rapamycin-dependent p70 S6 kinase phosphorylation at Thr421/Ser424 and Thr389, and rapamycin-independent phosphorylation of neurofilaments at the SMI34 epitope. Although zinc could induce cell proliferation and cell growth, and increased phosphorylation of neurofilaments, only cell growth appeared to be related to p7056kinase activation. © 2005 Lippincott Williams & Wilkins, Inc.