Low molecular weight GTP-binding proteins are molecular switches that are believed to play pivotal roles in cell growth, differentiation, cytoskeletal organization, and vesicular trafficking. Rab proteins are key players in the regulation of vesicular transport, while Rho family members control actin-dependent cell functions, i.e. the regulation of cytoskeletal organization in response to extracelluar growth factors and in dendritic neuron development. In this study, we have examined the regulation of small GTP-binding proteins that are implicated in neurosecretion and differentiation of neuron during ageing processes. Comparison of small GTP-binding proteins from the synaptosome and crude synaptic vesicles (LP2 membranes) of 2 months and 20 months old rat brain respectively showed no difference in the level of Rab family proteins (Rab3A and Rab5A). However, Rho family proteins such as RhoA and Cdc42 were elevated in LP2 membranes of the aged brain. The dissociation of Rab3A by Ca2+/calmodulin (CaM) from SV membranes was not changed during aging. Ca2+/CaM stimulated phosphorylation of the 22 and 55-kDa proteins in SV membranes from the aged rat brain, and inhibited phosporylation of 30-kDa proteins. GTPgammaS inhibited phosphorylation of the 100-kDa proteins and stimulated phosphorylation of the 70 kDa in LP2 membranes from both the young and aged rat brains, whereas GDPbetaS caused just the opposite reaction. These results suggest that protein phosphorylation and regulation of Rho family GTPases in rat brain appears to be altered during ageing processes.
*Aging ; Animal ; Brain/metabolism ; Calcium/pharmacology ; Cattle ; Comparative Study ; GTP-Binding Proteins/*metabolism ; Guanosine 5'-O-(3-Thiotriphosphate)/metabolism ; Molecular Weight ; Phosphorylation/drug effects ; Rats ; Rats, Sprague-Dawley ; Synaptic Membranes/*metabolism ; Synaptosomes/*metabolism ; cdc42 GTP-Binding Protein/biosynthesis/metabolism ; rab3A GTP-Binding Protein/metabolism ; rab5 GTP-Binding Proteins/metabolism ; rhoA GTP-Binding Protein/biosynthesis/metabolism

Low molecular weight GTP-binding proteins are molecular switches that are believed to play pivotal roles in cell growth, differentiation, cytoskeletal organization, and vesicular trafficking. Rab proteins are key players in the regulation of vesicular transport, while Rho family members control actin-dependent cell functions, i.e. the regulation of cytoskeletal organization in response to extracelluar growth factors and in dendritic neuron development. In this study, we have examined the regulation of small GTP-binding proteins that are implicated in neurosecretion and differentiation of neuron during ageing processes. Comparison of small GTP-binding proteins from the synaptosome and crude synaptic vesicles (LP2 membranes) of 2 months and 20 months old rat brain respectively showed no difference in the level of Rab family proteins (Rab3A and Rab5A). However, Rho family proteins such as RhoA and Cdc42 were elevated in LP2 membranes of the aged brain. The dissociation of Rab3A by Ca2+/calmodulin (CaM) from SV membranes was not changed during aging. Ca2+/CaM stimulated phosphorylation of the 22 and 55-kDa proteins in SV membranes from the aged rat brain, and inhibited phosporylation of 30-kDa proteins. GTPgammaS inhibited phosphorylation of the 100-kDa proteins and stimulated phosphorylation of the 70 kDa in LP2 membranes from both the young and aged rat brains, whereas GDPbetaS caused just the opposite reaction. These results suggest that protein phosphorylation and regulation of Rho family GTPases in rat brain appears to be altered during ageing processes.
*Aging ; Animal ; Brain/metabolism ; Calcium/pharmacology ; Cattle ; Comparative Study ; GTP-Binding Proteins/*metabolism ; Guanosine 5'-O-(3-Thiotriphosphate)/metabolism ; Molecular Weight ; Phosphorylation/drug effects ; Rats ; Rats, Sprague-Dawley ; Synaptic Membranes/*metabolism ; Synaptosomes/*metabolism ; cdc42 GTP-Binding Protein/biosynthesis/metabolism ; rab3A GTP-Binding Protein/metabolism ; rab5 GTP-Binding Proteins/metabolism ; rhoA GTP-Binding Protein/biosynthesis/metabolism

OBJECTIVETo detect the expression of RhoC protein in human primary hepatocellular carcinoma (HCC) and pericancerous liver (PCL) tissues and its relation to HCC prognosis.

METHODSImmunohistochemical method was used to detect the expression of RhoC protein in HCC, PCL of 43 patients. Thirty-six patients were followed up after they received radical resection.

RESULTThe expression of RhoC protein in HCC was significantly higher than that in PCL. Rhoc expression was increased in cases with poor differentiation, portal vascular invasion, unintact envelope and multiple masses. The survival analysis showed that HCC with lower RhoC protein expression had better clinical outcomes.

CONCLUSIONRhoC protein expression is correlated with infiltration and metastasis in HCC. RhoC protein can be used as a prognostic indicator for HCC.

Adult ; Carcinoma, Hepatocellular ; metabolism ; pathology ; Female ; Humans ; Liver Neoplasms ; metabolism ; pathology ; Male ; Neoplasm Invasiveness ; Neoplasm Metastasis ; Prognosis ; rho GTP-Binding Proteins ; biosynthesis ; genetics ; rhoC GTP-Binding Protein

OBJECTIVETo investigate the expression of RhoA, RhoC and their effector ROCK-1 in four ovarian cancer cell lines in vitro and their correlation with invasiveness.

METHODSExpression of RhoA, RhoC and ROCK-1 mRNA and protein in four ovarian cancer cell lines SW626, Skov-3, A2780 and Caov-3 was detected by RT-PCR and Western blot assay. Invasion assay was done in Boyden chamber.

RESULTSThe expression levels of RhoA, RhoC and ROCK-1 mRNA and protein varied in the four different cell lines examined. The expression level of RhoC, but not RhoA and ROCK-1, was significantly correlated with the invasive capability of these cells in vitro (r = 0.95, P < 0.01). Expression of RhoA at the level of transcription was not correlated with that at the translation level. The expression of RhoA and RhoC did not correlate with that of ROCK-1.

CONCLUSIONExpression level of RhoC may serve as an independent parameter in evaluating metastasis and become a new target in inhibiting ovarian cancer metastasis.

Cell Line, Tumor ; Cell Movement ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; Intracellular Signaling Peptides and Proteins ; Neoplasm Invasiveness ; Neoplasm Metastasis ; Ovarian Neoplasms ; genetics ; metabolism ; pathology ; Phenotype ; Protein Biosynthesis ; Protein-Serine-Threonine Kinases ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Transcription, Genetic ; rho GTP-Binding Proteins ; biosynthesis ; genetics ; rho-Associated Kinases ; rhoA GTP-Binding Protein ; biosynthesis ; genetics ; rhoC GTP-Binding Protein

OBJECTIVETo investigate the expressions of RhoC and osteopontin (OPN) protein in esophageal squamous carcinoma (ESC) and their association with the biological behavior of ESC.

METHODSThe expressions of RhoC and OPN protein were detected in 80 ESC cases by immunohistochemistry.

RESULTSThe positive expression rate of RhoC was 66.25% in these ESC cases. The rate was significantly higher in cases with lymph node metastasis than in those without (r(s)=-2.115, P<0.05), but RhoC expression was not associated with the tumor diameter, differentiation or TNM grade (P>0.05). The RhoC-positive patients had significantly shorter survival time than the negative patients (P<0.001). All the 80 ESC patients were positive for OPN expression, and OPN expression levels were correlated with the differentiation (chi(2)=10.766, P<0.05) and lymph node metastasis of the tumor (r(s)=-2.289, P<0.05), but not with the tumor diameter or TNM grade (P>0.05). Higher expression level of OPN was closely related to shorter survival time of the patients (P<0.05). A positive correlation was found between RhoC protein and OPN expressions (r(s)= 0.408, P<0.001) in these cases.

CONCLUSIONThe expressions of RhoC and OPN protein are closely related to lymph node metastasis of ESC and the patients survival time, and therefore may serve the purpose of prognostic evaluation of ESC.

Adult ; Aged ; Aged, 80 and over ; Biomarkers, Tumor ; biosynthesis ; Carcinoma, Squamous Cell ; metabolism ; pathology ; Esophageal Neoplasms ; metabolism ; pathology ; Female ; Humans ; Immunohistochemistry ; Male ; Middle Aged ; Osteopontin ; biosynthesis ; Prognosis ; Survival Analysis ; rho GTP-Binding Proteins ; biosynthesis ; rhoC GTP-Binding Protein

OBJECTIVETo study the relationship between a G/T substitution at position -88 of myxovirus resistance-1 gene (MxA) and the self-limiting or chronic infection of HBV.

METHODSBlood samples from 100 patients with self-limiting HBV infection (positive anti-HBs and anti-HBc) and from 340 patients with chronic HBV infection were collected. MxA-88 G/T polymorphism was typed using a protocol based on competitively differentiated-polymerase chain reaction. For statistical analysis, odds ratio and chi-square test were used.

RESULTSThe detective rate of G/G genotype (low expression genotype) of MxA-88 G/T was 50.2% (221/440), those of T/T genotype (high expression genotype) and G/T heterozygous genotype were 5.5% (24/440) and 44.3% (195/440). Compared to patients with chronic infection, patients with self-limiting infection had lower frequency of G/G genotype (41.0% vs 52.9%, P < 0.05) or G allele (62.5% vs 75.9%, P < 0.01) and had higher frequency of T/T genotype (16.0% vs 2.4%, P < 0.01) or T allele (37.5% vs 24.1%, P < 0.01), but there was no significant difference in the G/T heterozygous genotype.

CONCLUSIONSMxA gene -88 G/T polymorphism influences the natural outcomes of HBV infection to some extent. This SNP of MxA gene may be used as a clinical prognostic marker of HBV infection.

Adult ; Biomarkers ; Female ; GTP-Binding Proteins ; biosynthesis ; genetics ; Genotype ; Hepatitis B, Chronic ; genetics ; Humans ; Male ; Myxovirus Resistance Proteins ; Polymorphism, Single Nucleotide ; genetics ; Prognosis

OBJECTIVETo investigate the expression of NOEY2 gene in breast cancer tissue and its relation to clinicopathological and other molecular parameters.

METHODSThe mRNA expression of NOEY2 gene was monitored in benign and malignant breast lesions by RT-PCR and in situ hybridization (ISH) with transcripted antisense RNA probes. The protein expression of estrogen receptor (ER), Ki67, p27 and p21(WAF1) in the 60 breast cancer lesions was detected by immunohistochemical method.

RESULTSAll 6 benign lesions, and 13 (72.2%) of the 18 breast cancers were NOEY2 positive by RT-PCR. By ISH, positive NOEY2 was obtained in all 10 benign lesions but only in 31 (51.7%) of the 60 breast cancer lesions. The difference was statistically significant (P = 0.025). NOEY2 positive rate tended to decrease with the increase of histological grade. However, NOEY2 expression was negatively correlated with the status of axillary lymph nodes. The positive NOEY2 rate was 75% in those without lymph node metastasis but only 26.7% in those with metastasis (P < 0.001). No correlation with other clinicopathological parameters including ER, Ki67, p27 or p21(WAF1) were found.

CONCLUSIONNOEY2 gene may be related with the pathogenesis of breast cancer. A link between NOEY2 loss expression and the spreading mechanism of breast cancer may possibly exist.

Breast Neoplasms ; metabolism ; Female ; Gene Expression ; Humans ; In Situ Hybridization ; RNA, Messenger ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; rho GTP-Binding Proteins ; biosynthesis ; genetics

OBJECTIVETo explore the protein factors that could interact with the testis-specific protein encoded by HSD-3.8 gene (GenBank Accession Number AF311312) related with female fertilization.

METHODSYeast two-hybrid system was used to screen the human ovary MATCHMAKER cDNA library with constructed "bait plasmid" containing the 0.7 kb fragment (HSD-0.7) of HSD-3.8. The interaction with the positive fragments using a series of truncated bait plasmids was investigated.

RESULTSOne positive gene fragment was obtained, which coded for 144 amino acids of the C-terminus of human G protein beta subunit 1. Truncated bait plasmids couldn't interact with the fish protein fragment in yeast.

CONCLUSIONSThe protein encoded by HSD-3.8 gene may function through G protein signal transduction pathway and the interaction depends on the integration of the bait protein.

Adenosine Triphosphate ; metabolism ; Adult ; Antigens, Surface ; DNA-Binding Proteins ; genetics ; Female ; GTP-Binding Proteins ; genetics ; physiology ; Gene Library ; Humans ; Male ; Protein Biosynthesis ; Proteins ; genetics ; Spermatozoa ; chemistry ; physiology ; Synaptophysin ; Testis ; chemistry ; Two-Hybrid System Techniques ; Yeasts ; genetics

OBJECTIVETo explore the expression of the nucleostemin (NS) gene in prostate cancer (PCa) tissues and its clinical significance.

METHODSWe detected the NS expression in PCa, benign prostatic hyperplasia (BPH) and high grade prostatic intraepithelial neoplasia (HGPIN) tissues by RT-PCR and immunohistochemistry, and analyzed the correlation between the expression of the NS protein and the clinical variables of PCa.

RESULTSThe NS mRNA level was markedly higher in the PCa than in the BPH tissues. The rates of strongly positive, positive and weakly positive expressions of the NS protein were 48.8%, 36.6% and 12.2% in PCa, 4.0%, 32.0% and 56.0% in BPH, and 5.0%, 25.0% and 60.0% in HGPIN, respectively. The expression level of the NS protein was significantly higher in PCa than in BPH and HGPIN (P < 0.05). The expression of the NS gene was negatively correlated with the degree of cell differentiation in the PCa tissues, the worse the differentiation, the higher the NS expression level.

CONCLUSIONThe NS gene is highly expressed in PCa tissues and may have an important role in the adverse differentiation and malignant proliferation of prostate cancer.

Aged ; Carrier Proteins ; biosynthesis ; genetics ; GTP-Binding Proteins ; Humans ; Immunohistochemistry ; Male ; Middle Aged ; Neoplasm Staging ; Nuclear Proteins ; biosynthesis ; genetics ; Prostatic Neoplasms ; genetics ; metabolism ; pathology ; RNA, Messenger ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo investigate the influence of activated complement on the secretory function of peritoneal macrophage (PMphi) in the production of nitric oxide (NO) and tumor necrosis factor-alpha (TNF-alpha), especially in the role of different G-protein subtypes in this process after burns.

METHODSThe mice inflicted by 18% TBSA full-thickness scald was established and employed as the model. And the mice were divided into A (the complements were preserved and activated) and B (with intraperitoneal injection of CVF to deplete complement before scald) groups. The plasma of the mice in the two groups was collected at 6 postburn hour (PBH) and cultured with PMphi from normal mice. The PMphi were pretreated with pertussis toxin (PT) and with cholera toxin (CT). The NO and TNF-alpha levels in the supernatant of normal PMphi culture with different pretreatment were measured by Greiss assay.

RESULTSThe NO and TNF-alpha contents in group A [(80 +/- 12) micromol/L, (46 +/- 6)%] were obviously higher than those in group B [(34 +/- 5) micromol/L, (26 +/- 5)%, P < 0.01]. The NO content produced by PMphi (45 +/- 10 micromol/L) in A group decreased (P < 0.01), while the TNF-alpha activity (58 +/- 10)% increased by PT pretreatment (P < 0.05). On the contrary, the NO content produced by PMphi (105 +/- 18 micromol/L) in group A increased (P < 0.01), while the TNF-alpha activity (27 +/- 6)% decreased by CT pretreatment (P < 0.01).

CONCLUSIONThese results indicates that the secretory function of normal PMphi can be enhanced by complement activation after thermal injury, which might partly be due to the effect of activated complement components through complement receptor coupled G-protein. In the secretory function of complement stimulated Mphi, Gi protein has a major role in the production of NO, Gs protein is mainly involved in the secretion of TNF-alpha.

Animals ; Burns ; immunology ; metabolism ; Complement Activation ; Complement System Proteins ; metabolism ; Female ; GTP-Binding Proteins ; metabolism ; Macrophage Activation ; immunology ; Macrophages, Peritoneal ; secretion ; Male ; Mice ; Mice, Inbred Strains ; Nitric Oxide ; biosynthesis ; Signal Transduction ; Tumor Necrosis Factor-alpha ; biosynthesis