Hyaluronic acid (HA) binding to CD44 activates Rac1 and induces lamellipodia outgrowth.
Both cell adhesion protein CD44 and its main ligand hyaluronic acid (HA) are thought to be involved in several processes ultimately requiring cytoskeleton rearrangements. Here, we show that the small guanine nucleotide (GTP)-binding protein, Rac1, can be activated upon HA binding to CD44. When applied locally to a passive cell edge, HA promoted the formation of lamellipodial protrusions in the direction of the stimulus. This process was inhibited by the prior injection of cells with dominant-negative N17Rac recombinant protein or by pretreatment of cells with monoclonal anti-CD44 antibodies, interfering with HA binding, implying the direct involvement of CD44 in signaling to Rac1.
Oliferenko
S
S
Research Institute of Molecular Pathology (IMP), A-1030 Vienna, Austria.
Kaverina
I
I
Small
J V
JV
Huber
L A
LA
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D003593:Cytoplasm / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure*; D004847:Epithelial Cells / Q000502:physiology* / Q000648:ultrastructure; D005260:Female; D018960:Hyaluronan Receptors / Q000187:drug effects / Q000502:physiology*; D006820:Hyaluronic Acid / Q000494:pharmacology* / Q000502:physiology; D008321:Mammary Glands, Animal; D051379:Mice; D018715:Microscopy, Video; D011994:Recombinant Proteins / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D018960:Hyaluronan Receptors; D011994:Recombinant Proteins; D006820:Hyaluronic Acid; D020830:rac1 GTP-Binding Protein