The small GTP-binding protein rho regulates the assembly of focal adhesions and actin stress fibers in response to growth factors

AJ Ridley, A Hall - Cell, 1992 - cell.com
AJ Ridley, A Hall
Cell, 1992cell.com
Actin stress fibers are one of the major cytoskeletal structures in fibroblasts and are linked to
the plasma membrane at focal adhesions. rho, a ras-related GTP-binding protein, rapidly
stimulated stress fiber and focal adhesion formation when microinjected into serumstarved
Swiss 3T3 cells. Addition of serum produced a similar response, detectable within 2 min.
This activity was due to a lysophospholipid, most likely lysophosphatidic acid, bound to
serum albumin. Other growth factors including PDGF induced actin reorganization initially to …
Summary
Actin stress fibers are one of the major cytoskeletal structures in fibroblasts and are linked to the plasma membrane at focal adhesions. rho, a ras-related GTP-binding protein, rapidly stimulated stress fiber and focal adhesion formation when microinjected into serumstarved Swiss 3T3 cells. Addition of serum produced a similar response, detectable within 2 min. This activity was due to a lysophospholipid, most likely lysophosphatidic acid, bound to serum albumin. Other growth factors including PDGF induced actin reorganization initially to form membrane ruffles, and later, after 5 to 10 min, stress fibers. For all growth factors tested the stimulation of focal adhesion and stress fiber assembly was inhibited when endogenous rho function was blocked, whereas membrane ruffling was unaffected. These data imply that rho is essential specifically for the coordinated assembly of focal adhesions and stress fibers induced by growth factors.
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