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© The Rockefeller University Press, 0021-9525/2002/12/727-b $5.00
The Journal of Cell Biology, Volume 159, Number 5, 727-b-727

Microtubules get early release

Some growing MTs (black) get released from the centrosome and sent to the edge of the cell.

The centrosome is a nucleating center for microtubules (MTs) and the hub of the MT aster. On page 731, Abal et al. report that the centrosome in fibroblasts also seeds a second population of short MTs that are released and transported to the periphery. Both anchored and free MTs are needed for cell migration.

Abal et al. distinguished the two MT populations using GFP-tagged EB1, a protein that associates with growing MT plus ends. Visualization of EB1 in fibroblasts revealed that one set of MTs moved away from the centrosome toward the cell membrane more rapidly than could be explained by polymerization alone. The speed of this faster group stemmed from active transport of short but growing MTs by the motor dynein. Inhibition of dynein greatly diminished the number of free MTs. Free MTs were also reduced by increasing the centrosomal content of ninein, which anchors astral MTs to the centrosome.

The transport of free MTs participates in cell migration, as ninein-overexpressing fibroblasts could no longer migrate, but membrane ruffling (regulated by astral MTs) was not affected. Although it is still unclear how MT transport to the leading edge improves cell motility, proteins that break down focal adhesions might piggy-back on the free MTs. Alternatively, the short MTs may be captured by actin fibers to stabilize leading edge lamellipodia.

Nicole LeBrasseur

lebrasn{at}rockefeller.edu

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Microtubule release from the centrosome in migrating cells

Miguel Abal, Matthieu Piel, Veronique Bouckson-Castaing, Mette Mogensen, Jean-Baptiste Sibarita, and Michel Bornens
J. Cell Biol. 2002 159: 731-737. [Abstract] [Full Text] [PDF]

This Article Full Text (PDF, 261K) PPT slides of all figures Alert me when this article is cited Services Email this article Similar articles in this journal Alert me to new content in the JCB Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by LeBrasseur, N. Search for Related Content PubMed Articles by LeBrasseur, N. Related Collections Related Article Social Bookmarking                            What's this?