A New Member of the Rho Family, Rnd1, Promotes Disassembly of Actin Filament Structures and Loss of Cell Adhesion

• Published in: The Journal of cell biology 1998-04, Vol.141 (1), p.187-197
• Main Authors: Nobes, Catherine D., Lauritzen, Inger, Mattei, Marie-Geneviève, Paris, Sonia, Hall, Alan, Chardin, Pierre
• Format: Article
• Language: English
• Subjects: 3T3 Cells; Actins; Actins - physiology; Amino Acid Sequence; Animals; Antibodies; Brain - metabolism; Cattle; Cell Adhesion - physiology; Cells; Cellular biology; Chromosome Mapping; Chromosomes; Chromosomes, Human; Chromosomes, Human, Pair 12; Chromosomes, Human, Pair 17; Complementary DNA; DNA, Complementary; Epithelial cells; Fibroblasts; Fibroblasts - cytology; Fibroblasts - metabolism; Gene Library; GTP Phosphohydrolases - metabolism; GTP-Binding Proteins - biosynthesis; GTP-Binding Proteins - genetics; GTP-Binding Proteins - metabolism; Humans; In Situ Hybridization; Kinetics; Liver - metabolism; Lymphocytes - metabolism; Male; Mice; Microfilaments; Molecular Sequence Data; Multigene Family; Proteins; Recombinant Proteins - biosynthesis; Recombinant Proteins - isolation & purification; Recombinant Proteins - metabolism; Regular; rho GTP-Binding Proteins; Sequence Alignment; Sequence Homology, Amino Acid; Stress fibers; Swiss 3T3 cells; Testis - metabolism
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.141.1.187

Members of the Rho GTPase family regulate the organization of the actin cytoskeleton in response to extracellular growth factors. We have identified three proteins that form a distinct branch of the Rho family: Rnd1, expressed mostly in brain and liver; Rnd2, highly expressed in testis; and Rnd3/RhoE, showing a ubiquitous low expression. At the subcellular level, Rnd1 is concentrated at adherens junctions both in confluent fibroblasts and in epithelial cells. Rnd1 has a low affinity for GDP and spontaneously exchanges nucleotide rapidly in a physiological buffer. Furthermore, Rnd1 lacks intrinsic GTPase activity suggesting that in vivo, it might be constitutively in a GTP-bound form. Expression of Rnd1 or Rnd3/RhoE in fibroblasts inhibits the formation of actin stress fibers, membrane ruffles, and integrin-based focal adhesions and induces loss of cell-substrate adhesion leading to cell rounding (hence Rnd for "round"). We suggest that these proteins control rearrangements of the actin cytoskeleton and changes in cell adhesion.