Reelin molecules assemble together to form a large protein complex, which is inhibited by the function-blocking CR-50 antibody

Reelin molecules assemble together to form a large protein complex, which is inhibited by the function-blocking CR-50 antibody

^*Laboratory for Developmental Neurobiology, Brain Science Institute, RIKEN, Wako, Saitama, 351-0198, Japan; ^†Department of Molecular Neurobiology, Institute of DNA Medicine, Jikei University School of Medicine, Minato-ku, Tokyo, 105-8461; ^‖PRESTO, Japan Science and Technology Corporation, Kawaguchi, Saitama 332-0012; ^‡Department of Molecular Neurobiology and ^**Department of Fine Morphology, Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo, 108-8639; ^§Japan Advanced Institute of Science and Technology (JAIST), Hokuriku, Nomi-gun, Ishikawa, 923-1292; and ^¶Department of Chemistry, Tokyo Metropolitan University, Hachioji-shi, Tokyo, 192-03, Japan

Communicated by Pasko Rakic, Yale University School of Medicine, New Haven, CT (received for review February 1, 2000)

Abstract

Reelin is a key mediator of ordered neuronal alignment in the brain. Here, we demonstrate that Reelin molecules assemble with each other to form a huge protein complex both in vitro and in vivo. The Reelin–Reelin interaction clearly is inhibited by the function-blocking anti-Reelin antibody, CR-50, at a concentration known to inhibit Reelin function. This assembly is mediated by electrostatic interaction of the CR-50 epitope region. Recombinant CR-50 epitope fragments spontaneously constitute a soluble, string-like homopolymer with a regularly repeated structure composed of more than 40 monomers. Mutated Reelin, which lacks the CR-50 epitope region, cannot form a homopolymer and fails to induce efficient tyrosine phosphorylation of Disabled 1 (Dab1), which should occur to transduce the Reelin signal. These data suggest that Reelin exerts its biological function by composing a large protein assembly driven by the CR-50 epitope region, proposing a novel model of the Reelin signaling in neurodevelopment.

Footnotes

↵ ‡‡ To whom reprint requests and correspondence should be addressed at: Department of Molecular Neurobiology, Institute of DNA Medicine, Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo 105-8461, Japan. E-mail: kazunori{at}jikei.ac.jp.
Article published online before print: Proc. Natl. Acad. Sci. USA, 10.1073/pnas.160272497.
Article and publication date are at www.pnas.org/cgi/doi/10.1073/pnas.160272497
Abbreviations:

Dab1,

Disabled 1;

VLDLR,

very low density lipoprotein receptor;

CNR,

cadherin-related neuronal receptor;

En,

embryonic day n;

ApoER2,

apolipoprotein E receptor 2