Rho GTPases and Myelin Formation

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Rho GTPases and Myelin Formation

http://www.medicalnewstoday.com/medicalnews.php?newsid=53562

Tina Thurnherr, Yves Benninger, Xunwei Wu, Chrostek, Sven M.

Krause, Klaus-Armin Nave, Robin J. M. lin, Cord Brakebusch, Ueli

Suter, and Jo o B. Relvas

The formation of myelin sheaths is a carefully orchestrated process.

In the CNS, oligodendrocyte progenitor cells respond to signals in

their environment to proliferate and migrate, eventually

differentiating into mature cells capable of wrapping CNS axons in

sheet-like membranous extensions.

The membrane layers are the compacted by the exclusion of cytoplasm

to form myelin sheaths. Previous studies suggest that the Rho GTPases

Cdc42 and rac1 regulate oligodendrocyte development. Thurnherr et al.

sought to more precisely define their roles using Crerecombinase

technology to knock out Cdc42 or rac1 in the oligodendrocyte lineage.

The authors demonstrate that the two proteins are required in a

synergistic and dose-dependent manner for proper myelination but not

oligodendrocyte maturation or migration.

The absence of either protein led to an unusual myelin phenotype with

abnormal accumulation of cytoplasm in the inner tongue of compact

myelin sheaths and a reduction in myelin thickness.