Microtubules regulate migratory polarity through Rho/ROCK signaling in T cells.
BACKGROUND
Migrating leukocytes normally have a polarized morphology with an actin-rich lamellipodium at the front and a uropod at the rear. Microtubules (MTs) are required for persistent migration and chemotaxis, but how they affect cell polarity is not known.


RESULTS
Here we report that T cells treated with nocodazole to disrupt MTs are unable to form a stable uropod or lamellipodium, and instead often move by membrane blebbing with reduced migratory persistence. However, uropod-localized receptors and ezrin/radixin/moesin proteins still cluster in nocodazole-treated cells, indicating that MTs are required specifically for uropod stability. Nocodazole stimulates RhoA activity, and inhibition of the RhoA target ROCK allows nocodazole-treated cells to re-establish lamellipodia and uropods and persistent migratory polarity. ROCK inhibition decreases nocodazole-induced membrane blebbing and stabilizes MTs. The myosin inhibitor blebbistatin also stabilizes MTs, indicating that RhoA/ROCK act through myosin II to destabilize MTs.


CONCLUSIONS
Our results indicate that RhoA/ROCK signaling normally contributes to migration by affecting both actomyosin contractility and MT stability. We propose that regulation of MT stability and RhoA/ROCK activity is a mechanism to alter T-cell migratory behavior from lamellipodium-based persistent migration to bleb-based migration with frequent turning.
Takesono
Aya
A
University College London, Department of Biochemistry and Molecular Biology and Ludwig Institute for Cancer Research, London, United Kingdom.
Heasman
Sarah J
SJ
Wojciak-Stothard
Beata
B
Garg
Ritu
R
Ridley
Anne J
AJ
D045744:Cell Line, Tumor; D016764:Cell Polarity / Q000187:drug effects; D006801:Humans; D008870:Microtubules / Q000502:physiology*; D015739:Nocodazole / Q000494:pharmacology; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D054460:rho-Associated Kinases / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein; D015739:Nocodazole