Interaction of Neuronal Cdc2-like Protein Kinase with Microtubule-associated Protein Tau

Kazuya Sobue,Alka Agarwal-Mawal,Wei Li,Wei Sun,Yutaka Miura,Hemant K Paudel

doi:10.1074/jbc.m000784200

Kazuya Sobue, Alka Agarwal-Mawal + Show 4 more

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https://doi.org/10.1074/jbc.m000784200

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Abstract

Neuronal Cdc2-like protein kinase (NCLK), a approximately 58-kDa heterodimer, was isolated from neuronal microtubules (Ishiguro, K., Takamatsu, M., Tomizawa, K., Omori, A., Takahashi, M., Arioka, M., Uchida, T. and Imahori, K. (1992) J. Biol. Chem. 267, 10897-10901). The biochemical nature of NCLK-microtubule association is not known. In this study we found that NCLK is released from microtubules upon microtubule disassembly as a 450-kDa species. The 450-kDa species is an NCLK.tau complex, and NCLK-bound tau is in a nonphosphorylated state. Tau phosphorylation causes NCLK.tau complex dissociation, and phosphorylated tau does not bind to NCLK. In vitro, the Cdk5 subunit of NCLK binds to the microtubule-binding region of tau and NCLK associates with microtubules only in the presence of tau. Our data indicate that in brain extract NCLK is complexed with tau in a tau phosphorylation-dependent manner and that tau anchors NCLK to microtubules. Recently NCLK has been suggested to be aberrantly activated and to hyperphosphorylate tau in Alzheimer's disease brain (Patrick, G. N., Zukerberg, L., Nikolic, M., de la Monte, S., Dikkes, P, and Tsai, L.-H. (1999) Nature 402, 615-622). Our findings may explain why in Alzheimer's disease NCLK specifically hyperphosphorylates tau, although this kinase has a number of protein substrates in the brain.

Highlights

Neuronal Cdc2-like protein kinase (NCLK), a ϳ58-kDa heterodimer, was isolated from neuronal microtubules (Ishiguro, K., Takamatsu, M., Tomizawa, K., Omori, A., Takahashi, M., Arioka, M., Uchida, T. and Imahori, K. (1992) J
NCLK in Microtubule Fraction—When microtubules in a fresh brain homogenate were subjected to three cycles of temperature-induced assembly and disassembly, ϳ40, ϳ22, and ϳ20% of total NCLK in the brain homogenate was recovered within first (P1), second (P2), and third (P3) microtubule pellets, respectively (Table I)
The few minor contaminants in pellet 1 (P1) decreased in pellet 2 (P2)

Summary

Introduction

Neuronal Cdc2-like protein kinase (NCLK), a ϳ58-kDa heterodimer, was isolated from neuronal microtubules (Ishiguro, K., Takamatsu, M., Tomizawa, K., Omori, A., Takahashi, M., Arioka, M., Uchida, T. and Imahori, K. (1992) J. Mice lacking p35 do not show NCLK activity and display cortical lamination defects, seizures, and adult lethality [5] These observations indicate that NCLK plays an important role in brain development, neuronal differentiation, and neurite outgrowth. NCLK phosphorylates the microtubule-associated protein tau [10, 11] and neurofilaments [12, 13]. These data indicate that NCLK regulates neural signaling, vesicular exocytosis, neurotransmitter release, and microtubule dynamics. Mice overexpressing the p25 subunit to activate NCLK display hyperphosphorylated tau and disrupted neuronal cytoskeleton [17].

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