First published online September 28, 2005
Development 132, 2005e (2005)
© The Company of Biologists Limited
Microtubules: converging and extending insights
Early in development, morphogenetic movements known as convergent extension
(CE) convert the spherical egg into an elongated structure. During this
process, embryonic cells involved in CE develop actin-based lamellipodia and
become polarized. On p.
4599, Kwan and
Kirschner report that XLfc, a Rho-guanine nucleotide-exchange factor (GEF)
whose activity is controlled through binding to microtubules, controls cell
morphology during CE in Xenopus. Early in gastrulation, CE is briefly
sensitive to microtubule depolymerizing drugs. By visualizing actin and
microtubules simultaneously in live explants treated with drugs that affect
microtubule stability, the researchers show that it is the actual mass of
polymerized tubulin – and not the dynamics of the microtubule
cytoskeleton – that controls lamellipodia formation and subsequent CE.
Additional experiments indicate that, by binding a specific Rho-GEF,
microtubules act as a bulk regulator of Rho-family GTPases – which
control actin polymerization – and thus regulate cell polarity during
CE.
Related articles in Development:
- A microtubule-binding Rho-GEF controls cell morphology during convergent extension of Xenopus laevis
- Kristen M. Kwan and Marc W. Kirschner
Development 2005 132: 4599-4610.
[Abstract]
[Full Text]
