1997 Fiscal Year Final Research Report Summary
Identification and functional analysis of proteins involved in novel pathway for PLC activation.
| Project/Area Number |
08458184
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Structural biochemistry
|
|---|
| Research Institution | Fukushima Medical University |
|---|
Principal Investigator |
HOMMA Yoshimi Fukushima Medical University School of Medicine, Department of Biomolecular Science, Professor, 医学部, 教授 (60192324)
|
|---|
| Project Period (FY) |
1996 – 1997
|
| Keywords | intracellular signaling / inositol phospholipid / G protein / phospholipase C / actin / cytoskeleton |
|---|
| Research Abstract |
We recently cloned a novel signaling molecule, p122, that shows GAP activity specific for Rho and the ability to enhance the PIP_<> hydrolyzing activity of PLCdelta1 in vitro. Here we identified molecules interacting with p122 and analyzed the in vivo function of p122. Following results were obtained from this research project. 1) p122 interacted with a number of intracellular signaling molecules such as vinculin and p55.2) Microinjection of the GAP domain of p122 suppressed the formation of stress fibers and focal adhesions induced by lysophosphatidic acid. 3) Transfection of p122 also induced the morphological rounding of various adherent cells, followed by detachment from the substrate within 24 h. No stress fibers or focal adhesions were observed in the course of these changes. 4) The morphological changes caused by p122 were inhibited by coexpression of V14-RhoA, which is defective in an intrinsic GTPase activity. Analyses using deletion and point mutants demonstrated that the GAP domain of p122 is responsible for the morphological changes and detachment, and that arginine residues at positions 668 and 710 and a lysine residue at position 706 in the GAP domain of p122, all conserved among several Rho GAPs, are essential for stimulating the GTPase activity of Rho. 5) Using the Ca^<2+>-sensitive dye fluo-3, we found that microinjection of p122 evoked a rapid elevation of intracellular Ca^<2+> levels, suggesting that p122 stimulates the PIP_2 hydrolyzing activity of PLCdelta1 in vivo.
|
