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Originally published In Press as doi:10.1074/jbc.M701019200 on February 25, 2007
J. Biol. Chem., Vol. 282, Issue 16, 12319-12329, April 20, 2007
Process Elongation of Oligodendrocytes Is Promoted by the Kelch-related Protein MRP2/KLHL1*
Shuxian Jiang1,
Seyha Seng1,
Hava Karsenty Avraham,
Yigong Fu, and
Shalom Avraham2
From the
Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02115
Oligodendrocytes (OLGs) are generated by progenitor cells that are committed to differentiating into myelin-forming cells of the central nervous system. Rearrangement of the cytoskeleton leading to the extension of cellular processes is essential for the myelination of axons by OLGs. Here, we have characterized a new member of the Kelch-related protein family termed MRP2 (for Mayven-related protein 2) that is specifically expressed in brain. MRP2/KLHL1 is expressed in oligodendrocyte precursors and mature OLGs, and its expression is up-regulated during OLG differentiation. MRP2/KLHL1 expression was abundant during the specific stages of oligodendrocyte development, as identified by A2B5-, O4-, and O1-specific oligodendrocyte markers. MRP2/KLHL1 was localized in the cytoplasm and along the cell processes. Moreover, a direct endogenous association of MRP2/KLHL1 with actin was observed, which was significantly increased in differentiated OLGs compared with undifferentiated OLGs. Overexpression of MRP2/KLHL1 resulted in a significant increase in the process extension of rat OLGs, whereas MRP2/KLHL1 antisense reduced the process length of primary rat OLGs. Furthermore, murine OLGs isolated from MRP2/KLHL1 transgenic mice showed a significant increase in the process extension of OLGs compared with control wild-type murine OLGs. These studies provide insights into the role of MRP2/KLHL1, through its interaction with actin, in the process elongation of OLGs.
Received for publication, February 2, 2007
* This work was supported by National Institutes of Health Grants NS 39558 (to S. A.), CA 096805 (to H. A.), and NHLBI K18 PAR-02-069 (to H. A.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
The on-line version of this article (available at http://www.jbc.org) contains supplemental Fig. S1.
1 Both authors contributed equally to this work.
2 To whom correspondence should be addressed: 4 Blackfan Circle, Boston, MA 02115. Tel.: 617-667-0063; Fax: 617-975-6373 or 617-975-5240; E-mail: savraham{at}bidmc.harvard.edu.

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Copyright © 2007 by the American Society for Biochemistry and Molecular Biology.
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