Phospholipase Cgamma1 (PLCgamma1) plays an important role in controlling cellular proliferation and differentiation. PLCgamma1 is overexpressed in some tumors, and its overexpression induces solid tumors in nude mice. However, the regulatory mechanisms underlying PLCgamma1-induced cell proliferation are not fully understood. Here we show that overexpression of PLCgamma1 highly phosphorylated glycogen synthase kinase-3beta (GSK-3beta) at serine-9 in 3Y1 fibroblasts. Inhibition of protein kinase C (PKC)s with GF109203X abrogated GSK-3beta phosphorylation by PLCgamma1. We also found that steady-state level of cyclin D1 protein, but not cyclin D1 mRNA, was highly elevated in response to serum stimulation in PLCgamma1-transfected cells as compared with vector-transfected cells. Since GSK-3beta is involved in cyclin D1 proteolysis in response to mitogenic stimulation, PLCgamma1-mediated GSK-3beta phosphorylation may function as a regulation of cyclin D1 accumulation in PLCgamma1-overexpressing cells.
Animals ; Cyclin D1/metabolism ; Epidermal Growth Factor/pharmacology ; Fibroblasts ; Gene Expression ; Glycogen Synthase Kinase 3/chemistry/*metabolism ; Mitogens/pharmacology ; Phospholipase C/genetics/*metabolism ; Phosphorylation/drug effects ; Phosphoserine/*metabolism ; Protein Kinase C/antagonists & inhibitors/*metabolism ; Rats ; Signal Transduction

COP9 Signalosome Complex ; Carcinoma, Hepatocellular ; genetics ; metabolism ; Cyclin-Dependent Kinase Inhibitor p27 ; chemistry ; genetics ; metabolism ; Electrophoresis, Polyacrylamide Gel ; Gene Expression Regulation, Neoplastic ; Humans ; Intracellular Signaling Peptides and Proteins ; chemistry ; genetics ; metabolism ; Peptide Hydrolases ; chemistry ; genetics ; metabolism ; Phosphorylation ; Phosphoserine ; metabolism

AIMTo explore the effects of periphery injection of L-SOP on the activation of p38MAPK in spinal cord in formalin pain model in rats.

METHODSFourty-eight male Wistar rats were divided randomly into four groups (n=12): NS group and three different dose of L-SOP groups. For each group, 6 rats used to observe flinching and licking time every as nociception behavior 3 minutes in 1 hour after formalin injected and the other 6 rats used to observe the activation of p38(P-p38) by Western blotting.

RESULTSAll the three different groups of L-SOP could inhibit nociception behavior in the tonic phase,and 250 nmoVl/L and 500 nmol/L groups could suppress not only in the tonic phase but also in the acute phase. 250 nmol/L and 500 nmol/L groups could reduce activated or phosphorylated p38MAPK in spinal cord.

CONCLUSIONPeriphery injection of L-SOP can reduce nociceptive behavior and phosphorylated p38MAPK in the spinal cord in formalin-induced hyperalgia, it is suggested that there is functional expression of mGluRs III in the periphery and is involved in the processing of peripheral noxious informations.

Animals ; Formaldehyde ; Male ; Nociception ; physiology ; Pain ; chemically induced ; metabolism ; physiopathology ; Phosphoserine ; pharmacology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptors, Metabotropic Glutamate ; physiology ; Spinal Cord ; metabolism ; physiopathology ; p38 Mitogen-Activated Protein Kinases ; metabolism

Checkpoint kinase 1 (Chk1) and Chk2 are effector kinases in the cellular DNA damage response and impairment of their function is closely related to tumorigenesis. Previous studies revealed several substrate proteins of Chk1 and Chk2, but identification of additional targets is still important in order to understand their tumor suppressor functions. In this study, we screened novel substrates for Chk1 and Chk2 using substrate target motifs determined previously by an oriented peptide library approach. The potential candidates were selected by genome-wide peptide database searches and were examined by in vitro kinase assays. ST5, HDAC5, PGC-1alpha, PP2A PR130, FANCG, GATA3, cyclin G, Rad51D and MAD1alpha were newly identified as in vitro substrates for Chk1 and/or Chk2. Among these, HDAC5 and PGC-1alpha were further analyzed to substantiate the screening results. Immunoprecipitation kinase assay of full-length proteins and site-directed mutagenesis analysis of the target motifs demonstrated that HDAC5 and PGC-1alpha were specific targets for Chk1 and/or Chk2 at least in vitro.
Amino Acid Motifs ; Amino Acid Sequence ; *Consensus Sequence ; Genome, Human/*genetics ; Heat-Shock Proteins/chemistry/metabolism ; Histone Deacetylases/chemistry/metabolism ; Humans ; Molecular Sequence Data ; Peptide Fragments/chemistry/metabolism ; Phosphorylation ; Phosphoserine/metabolism ; Protein Kinases/*metabolism ; Protein-Serine-Threonine Kinases/*metabolism ; Substrate Specificity ; Transcription Factors/chemistry/metabolism