Sphingosine Kinase from Swiss 3T3 Fibroblasts: A Convenient Assay for the Measurement of Intracellular Levels of Free Sphingoid Bases

1994 ◽  
Vol 223 (2) ◽  
pp. 306-312 ◽  
Author(s):  
A. Olivera ◽  
J. Rosenthal ◽  
S. Spiegel

1986 ◽  
Vol 261 (3) ◽  
pp. 1187-1192
Author(s):  
K Kaibuchi ◽  
T Tsuda ◽  
A Kikuchi ◽  
T Tanimoto ◽  
T Yamashita ◽  
...  


2002 ◽  
Vol 157 (5) ◽  
pp. 819-830 ◽  
Author(s):  
Takahiro Tsuji ◽  
Toshimasa Ishizaki ◽  
Muneo Okamoto ◽  
Chiharu Higashida ◽  
Kazuhiro Kimura ◽  
...  

The small GTPase Rho acts on two effectors, ROCK and mDia1, and induces stress fibers and focal adhesions. However, how ROCK and mDia1 individually regulate signals and dynamics of these structures remains unknown. We stimulated serum-starved Swiss 3T3 fibroblasts with LPA and compared the effects of C3 exoenzyme, a Rho inhibitor, with those of Y-27632, a ROCK inhibitor. Y-27632 treatment suppressed LPA-induced formation of stress fibers and focal adhesions as did C3 exoenzyme but induced membrane ruffles and focal complexes, which were absent in the C3 exoenzyme-treated cells. This phenotype was suppressed by expression of N17Rac. Consistently, the amount of GTP-Rac increased significantly by Y-27632 in LPA-stimulated cells. Biochemically, Y-27632 suppressed tyrosine phosphorylation of paxillin and focal adhesion kinase and not that of Cas. Inhibition of Cas phosphorylation with PP1 or expression of a dominant negative Cas mutant inhibited Y-27632–induced membrane ruffle formation. Moreover, Crk-II mutants lacking in binding to either phosphorylated Cas or DOCK180 suppressed the Y-27632–induced membrane ruffle formation. Finally, expression of a dominant negative mDia1 mutant also inhibited the membrane ruffle formation by Y-27632. Thus, these results have revealed the Rho-dependent Rac activation signaling that is mediated by mDia1 through Cas phosphorylation and antagonized by the action of ROCK.



1989 ◽  
Vol 159 (1) ◽  
pp. 155-162 ◽  
Author(s):  
Christine Philipps ◽  
Stefan Rose-John ◽  
Gabriele Rincke ◽  
Gerhard Fürstenberger ◽  
Friedrich Marks


1989 ◽  
Vol 560 (1 Calcium Chann) ◽  
pp. 116-117 ◽  
Author(s):  
ANTONIO PERES


2001 ◽  
Vol 114 (3) ◽  
pp. 549-562 ◽  
Author(s):  
D.A. Davy ◽  
H.D. Campbell ◽  
S. Fountain ◽  
D. de Jong ◽  
M.F. Crouch

The flightless I protein contains an actin-binding domain with homology to the gelsolin family and is likely to be involved in actin cytoskeletal rearrangements. It has been suggested that this protein is involved in linking the cytoskeletal network with signal transduction pathways. We have developed antibodies directed toward the leucine rich repeat and gelsolin-like domains of the human and mouse homologues of flightless I that specifically recognize expressed and endogenous forms of the protein. We have also constructed a flightless I-enhanced green fluorescent fusion vector and used this to examine the localization of the expressed protein in Swiss 3T3 fibroblasts. The flightless I protein localizes predominantly to the nucleus and translocates to the cytoplasm following serum stimulation. In cells stimulated to migrate, the flightless I protein colocalizes with beta-tubulin- and actin-based structures. Members of the small GTPase family, also implicated in cytoskeletal control, were found to colocalize with flightless I in migrating Swiss 3T3 fibroblasts. LY294002, a specific inhibitor of PI 3-kinase, inhibits the translocation of flightless I to actin-based structures. Our results suggest that PI 3-kinase and the small GTPases, Ras, RhoA and Cdc42 may be part of a common functional pathway involved in Fliih-mediated cytoskeletal regulation. Functionally, we suggest that flightless I may act to prepare actin filaments or provide factors required for cytoskeletal rearrangements necessary for cell migration and/or adhesion.



1988 ◽  
Vol 411 (5) ◽  
pp. 554-557 ◽  
Author(s):  
A. Peres ◽  
R. Zippel ◽  
E. Sturani ◽  
G. Mostacciuolo


1991 ◽  
Vol 1092 (3) ◽  
pp. 397-400 ◽  
Author(s):  
L. Morello ◽  
E. Sturani ◽  
M.G. Cattaneo ◽  
R. Brambilla ◽  
A. Vicario ◽  
...  


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