Anti-Infective Agents ; pharmacology ; Bacterial Outer Membrane Proteins ; genetics ; physiology ; Ciprofloxacin ; pharmacology ; DNA Gyrase ; genetics ; Drug Resistance, Bacterial ; Membrane Proteins ; genetics ; physiology ; Membrane Transport Proteins ; genetics ; physiology ; Mutation ; Pseudomonas aeruginosa ; drug effects

Drug Resistance ; Hormones ; pharmacology ; Humans ; Membrane Proteins ; genetics ; Nephrotic Syndrome ; genetics

OBJECTIVETo explore the effect of substance P (SP) on the functional proteins on plasma membrane of neutrophil (Np).

METHODThe response of Np to SP was examined by measuring the level of respiratory burst, the activities of ACP and ALP, the fluoroscopy intensity of CR3, CD45 and FM-LP.

RESULTSIt was found that SP could increase respiratory burst of Np, decrease the activity of acid phosphatase (ACP), but had no effect on alkaline phosphatase (ALP). SP could also promote the amount of CD45, complement receptor type 3 (CR3) and N-Formyl-Met-Leu-Phe (FMLP) receptors.

CONCLUSIONThe results showed that the effects of SP on functional proteins in human Np membrane were universality and diversity. It implied that SP could affect various inflammation responses in Np.

Acid Phosphatase ; metabolism ; Humans ; Membrane Proteins ; physiology ; Neutrophils ; metabolism ; Respiratory Burst ; Substance P ; pharmacology

We previously reported that nidogen is an extracellular matrix protein regulating Schwann cell proliferation and migration. Since Schwann cells play a critical role in peripheral nerve regeneration, nidogen may play a role in it via regulation of Schwann cells. Here, we demonstrate direct evidence that nidogen induces elongation of regenerative axon growth of adult sensory neurons, and that the effect is Schwann cell dependent. Continuous infusion of recombinant ectodomain of tumor endothelial marker 7, which specifically blocks nidogen function in Schwann cells, suppressed regenerative neurite growth in a sciatic nerve axotomy model. Taken together, it is likely that nidogen is required for proper regeneration of peripheral nerves after injury.
Animals ; Axotomy ; Cell Movement ; Cell Proliferation ; Male ; Membrane Glycoproteins/*physiology ; Membrane Proteins/pharmacology ; *Nerve Regeneration ; Nerve Tissue Proteins/pharmacology ; Neurites/drug effects/*physiology/ultrastructure ; Rats ; Rats, Sprague-Dawley ; Recombinant Proteins/pharmacology ; Schwann Cells/cytology/*physiology ; Sensory Receptor Cells/*physiology

Pectobacterium carotovorum subsp. carotovorum is one of the world's top ten plant pathogens, mainly infecting cruciferous economic crops and ornamental flowers. In this study, an antibacterial gene cpxP (Gene ID: 29704421) was cloned from the genome of Pectobacterium carotovorum subsp. carotovorum, and constructed on the prokaryotic expression plasmid pET-15b, and the recombinant plasmid was transformed into Escherichia coli BL21 (DE3), then stability and bacteriostatic experiments of the purified CpxP protein were performed. The final concentration of IPTG was 1 mmol/L, obtaining high-efficiency exogenous expression of the CpxP protein. There was no other protein after purification, and the destined protein exhibited good thermal stability and pH stability. The antibacterial test results showed that the inhibition rate of the CpxP protein on carrot slice was 44.89% while the inhibition rate on potato slice was 59.41%. To further explain its antibacterial mechanism, studying the spatial structure of this protein can provide new ideas for the control of soft rot and new protein pesticide targets.
Anti-Bacterial Agents ; pharmacology ; Bacteria ; drug effects ; Bacterial Proteins ; isolation & purification ; pharmacology ; Escherichia coli ; genetics ; Membrane Proteins ; isolation & purification ; pharmacology ; Pectobacterium carotovorum ; genetics ; metabolism ; Plasmids ; genetics

OBJECTIVETo investigate the differentially expressed mitochondrial proteins in hydroxycamptothecin (HCPT)-treated SMMC-7721 cells by comparative proteomic analysis.

METHODSApoptosis of SMMC-7721 cells were induced by using HCPT and their mitochondria were isolated with a mitochondria isolation kit for cultured cells. Three different solubility protein fractions were extracted with ReadyPrep Sequential Extraction Kit and were separated by two-dimensional gel electrophoresis (2-DE). PDQuest software was used to differentiate mitochondrial proteins between control cells and HCPT-treated cells. Matrix assisted laser desorption/ionization time of flying mass spectrometry (MALDI-TOF-MS) was used to identify some of the different proteins.

RESULTSHighly purified mitochondria and high resolution 2-DE patterns of the proteins were obtained. Forty-four mitochondrial protein spots from the HCPT-treated cells showed different expressions compared to those of the control cells. Twenty of the different protein spots were analyzed by MALDI-TOF-MS.

CONCLUSIONDifferently expressed mitochondrial proteins in HCPT-treated cells and control cells were obtained in this study. This will be of help to understand the mechanism by which HCPT induces cell apoptosis.

Antineoplastic Agents, Phytogenic ; pharmacology ; Camptothecin ; analogs & derivatives ; pharmacology ; Cell Line, Tumor ; Humans ; Membrane Potentials ; drug effects ; Mitochondrial Proteins ; metabolism ; Proteomics

Human salivary histatin 1 (Hst1) exhibits a series of cell-activating properties, such as promoting cell spreading, migration, and metabolic activity. We recently have shown that fluorescently labeled Hst1 (F-Hst1) targets and activates mitochondria, presenting an important molecular mechanism. However, its regulating signaling pathways remain to be elucidated. We investigated the influence of specific inhibitors of G protein-coupled receptors (GPCR), endocytosis pathways, extracellular signal-regulated kinases 1/2 (ERK1/2) signaling, p38 signaling, mitochondrial respiration and Na+/K+-ATPase activity on the uptake, mitochondria-targeting and -activating properties of F-Hst1. We performed a siRNA knockdown (KD) to assess the effect of Sigma-2 receptor (S2R) /Transmembrane Protein 97 (TMEM97)-a recently identified target protein of Hst1. We also adopted live cell imaging to monitor the whole intracellular trafficking process of F-Hst1. Our results showed that the inhibition of cellular respiration hindered the internalization of F-Hst1. The inhibitors of GPCR, ERK1/2, phagocytosis, and clathrin-mediated endocytosis (CME) as well as siRNA KD of S2R/TMEM97 significantly reduced the uptake, which was accompanied by the nullification of the promoting effect of F-Hst1 on cell metabolic activity. Only the inhibitor of CME and KD of S2R/TMEM97 significantly compromised the mitochondria-targeting of Hst1. We further showed the intracellular trafficking and targeting process of F-Hst1, in which early endosome plays an important role. Overall, phagocytosis, CME, GPCR, ERK signaling, and S2R/TMEM97 are involved in the internalization of Hst1, while only CME and S2R/TMEM97 are critical for its subcellular targeting. The inhibition of either internalization or mitochondria-targeting of Hst1 could significantly compromise its mitochondria-activating property.
Endocytosis/physiology* ; Histatins/pharmacology* ; Humans ; Membrane Proteins ; Mitochondria/metabolism* ; RNA, Small Interfering/pharmacology* ; Receptors, G-Protein-Coupled/metabolism* ; Receptors, sigma

BACKGROUNDQacA, a main exporter mediating the multidrug-resistance of Staphylococcus aureus to a variety of antiseptics and disinfectants, possesses a topology of 14 alpha-helical transmembrane segments (TMS). Our study aimed to determine the importance and topology of amino acid residues in and flanking the cytoplasmic end of TMS5.

METHODSSite-directed mutagenesis was used to mutate 5 residues, including L146, A147, V148, W149 and S150, into cysteine. A minimum inhibitory concentration (MIC) and transport assay with or without N-ethylmaleimide (NEM) were performed to analyse the function of these mutants.

RESULTSAll of the mutants showed comparable protein expression levels. MIC analysis suggested that mutant W149C showed low resistance levels to the drugs, but the mutations at L146, A147, V148, and S150C had little or no effect on the resistance level. And the results of the fluorimetric transport assay were in agreement with those of MIC analysis, that is to say, W149C did not allow transport to the substrates to be tested, while the other mutants retained significant transport ability. The reaction of the different mutant proteins with Fluorescein-NEM revealed that the mutant L146C was highly reactive with NEM; the W149C and S150C mutants were moderately reactive; A147C was barely reactive and V148C showed no reactivity.

CONCLUSIONSThe study identified that residues W149 and S150 situated at the interface of the aqueous: lipid junction as functionally important residues, probably involved in the substrate binding and translocation of QacA.

Bacterial Proteins ; chemistry ; physiology ; Drug Resistance, Bacterial ; Ethylmaleimide ; pharmacology ; Indoles ; metabolism ; Membrane Transport Proteins ; chemistry ; physiology ; Structure-Activity Relationship

OBJECTIVETo explore the effects of TNF alpha on the expression of sterol regulatory element binding proteins cleavage activating protein (SCAP) and triglyceride contents in cells of a model of cultured steatotic hepatocytes.

METHODSA steatotic hepatocytes model was established by treating L-02 cell strain with oleic acid. The cells were treated with TNF alpha and/or TNF alpha antibody. The cells were divided into six groups: a control group (C), a model group (F), a control group with TNF alpha (C1), a control group with TNFalpha antibody (C2), a model group with TNFalpha(F1) and a model group with TNFalpha antibody (F2). The expression of SREBP-1c mRNA was measured with RT-PCR; the protein expression of SCAP was measured by Western blot; lipid droplets in the hepatocytes were observed with oil red O staining; the contents of triglyceride in hepatocytes were measured with an analytical kit.

RESULTSThe mRNA expression of SCAP in the groups treated with TNF alpha were upregulated compared with those of the control group (C1 vs C increased 67%, F1 vs F increased 55%, F = 212.98), the protein expression of SCAP in the groups treated with TNF alpha was upregulated compared with those of the control group (C1 vs C increased 45%, F1 vs F increased 95%, F = 104.3), and triglyceride contents in hepatocytes of these groups were increased compared with those of the control group [C (2.02+/-0.67) mg/10(7) cells, F(7.79+/-1.35) mg/10(7) cells, F1(13.36+/-1.99) mg/10(7) cells, F = 82.94].

CONCLUSIONTNF alpha upregulates the expression of SCAP and promotes the synthesis of triglyceride; it probably participates in the process of developing steatosis of hepatocytes.

Cell Line ; Hepatocytes ; drug effects ; metabolism ; Humans ; Intracellular Signaling Peptides and Proteins ; metabolism ; Membrane Proteins ; metabolism ; Tumor Necrosis Factor-alpha ; pharmacology

OBJECTIVETo construct pBV-BPI600-Fcgamma1(700) recombinant expression vector, to transform it into Escherichia coli DH5alpha, and to induce the expression of BPI23-Fcgamma1 anti-bacterial recombinant protein.

METHODSGenes coding for BPI23 and Fcgamma1 were amplified by RT-PCR from mRNA extracted from HL-60 cell and normal human leukocytes; recombinant cloning vector and recombinant expression vector were then constructed. pBV-BPI600-Fcgamma1(700) recombinant expression vector was transformed into the competent Escherichia coli DH5alpha and BPI23-Fcgamma1 recombinant protein was expressed by a temperature-induced method.

RESULTS(1) Expected amplified products BPI600hp and Fcgamma1(700bp) were obtained by RT-PCR method. (2) pUC18-BPI180, pUC18-BPI420 and pUC18-Fcgamma1(700) recombinant cloning vector were successfully constructed, and sequences were identical with the reported ones. 3) pBV-BPI600-Fcgamma1(700) recombinant expression vector was successfully constructed, and the enzyme digestion analysis showed an expected result. (4) The expression level of BPI23-Fcgamma1 recombinant protein accounted for 20% of total bacterial proteins. (5) The renatured BPI23-Fcgamma1 recombinant protein showed bacteriocidal activity and biological function of complement fixation, and opsonization.

CONCLUSIONpBV-BPI600-Fcgamma1(700) recombinant expression vector was successfully constructed, and BPI23-Fcgamma1 recombinant protein with double biological activity of BPI and IgGFc was expresed in Escherichia coli.

Antimicrobial Cationic Peptides ; Blood Bactericidal Activity ; drug effects ; Blood Proteins ; biosynthesis ; genetics ; pharmacology ; Carrier Proteins ; biosynthesis ; genetics ; pharmacology ; Cell Adhesion Molecules ; Escherichia coli ; genetics ; metabolism ; Genetic Vectors ; HL-60 Cells ; Humans ; Membrane Proteins ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; pharmacology