scholarly journals Structural Analysis of the Peptide Pheromone Receptor PlnB, a Histidine Protein Kinase from Lactobacillus plantarum

2003 ◽  
Vol 185 (23) ◽  
pp. 6913-6920 ◽  
Author(s):  
Ola Johnsborg ◽  
Dzung B. Diep ◽  
Ingolf F. Nes
Keyword(s):  
Protein Kinase ◽  
Lactobacillus Plantarum ◽  
Domain Switching ◽  
Transmembrane Domain ◽  
Cell Communication ◽  
Threshold Concentration ◽  
Membrane Topology ◽  
Histidine Protein Kinase ◽  
Transmembrane Segments ◽  
Physiological Processes

ABSTRACT Intercellular communication plays a key role in the regulation of several physiological processes in gram-positive bacteria. Cell-cell communication is often mediated by secreted inducer peptide pheromones (IPs), which upon reaching a threshold concentration in the environment specifically activate a cognate membrane-localized histidine protein kinase (HPK). Interestingly, the majority of IP-activated HPKs fall into one distinct subfamily (HPK10). As part of an effort to study the mechanism underlying pheromone-mediated activation of the HPK10 subfamily, the present work investigated the membrane topology of PlnB from Lactobacillus plantarum. Gene fusion experiments with Escherichia coli and Lactobacillus sakei, using alkaline phosphatase, β-lactamase, and β-galactosidase reporter fusions, suggested that PlnB is anchored to the cytoplasmic membrane via seven transmembrane segments. By domain switching between HPK10 members, it was demonstrated that the determinants for pheromone binding and specificity are contained within the transmembrane domain. The results also indicate that the mechanism of signal transduction, in which the final transmembrane segment apparently plays a key role, is conserved between members of the HPK10 subfamily.

scholarly journals Targeted disruption of PKC from AKAP Signaling Complexes

2021 ◽  
Author(s):  
Ameya J. Limaye ◽  
George N. Bendzunas ◽  
Eileen Kennedy
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Signaling Pathways ◽  
Protein Interactions ◽  
Protein Protein Interactions ◽  
Targeted Disruption ◽  
Physiological Processes ◽  
Kinase C ◽  
P Protein

Protein Kinase C (PKC) is a member of the AGC subfamily of kinases and regulates a wide array of signaling pathways and physiological processes. Protein-protein interactions involving PKC and its...

scholarly journals Microarray Analysis of a Two-Component Regulatory System Involved in Acid Resistance and Proteolytic Activity in Lactobacillus acidophilus

2005 ◽  
Vol 71 (10) ◽  
pp. 5794-5804 ◽  
Author(s):  
M. Andrea Azcarate-Peril ◽  
Olivia McAuliffe ◽  
Eric Altermann ◽  
Sonja Lick ◽  
W. Michael Russell ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Proteolytic Activity ◽  
Lactobacillus Acidophilus ◽  
Regulatory System ◽  
Probiotic Bacterium ◽  
Transport Systems ◽  
Logarithmic Phase ◽  
Histidine Protein Kinase ◽  
Regulatory Systems ◽  
Two Component

ABSTRACT Two-component regulatory systems are one primary mechanism for environmental sensing and signal transduction. Annotation of the complete genome sequence of the probiotic bacterium Lactobacillus acidophilus NCFM revealed nine two-component regulatory systems. In this study, the histidine protein kinase of a two-component regulatory system (LBA1524HPK-LBA1525RR), similar to the acid-related system lisRK from Listeria monocytogenes (P. D. Cotter et al., J. Bacteriol. 181:6840-6843, 1999), was insertionally inactivated. A whole-genome microarray containing 97.4% of the annotated genes of L. acidophilus was used to compare genome-wide patterns of transcription at various pHs between the control and the histidine protein kinase mutant. The expression pattern of approximately 80 genes was affected by the LBA1524HPK mutation. Putative LBA1525RR target loci included two oligopeptide-transport systems present in the L. acidophilus genome, other components of the proteolytic system, and a LuxS homolog, suspected of participating in synthesis of the AI-2 signaling compound. The mutant exhibited lower tolerance to acid and ethanol in logarithmic-phase cells and poor acidification rates in milk. Supplementation of milk with Casamino Acids essentially restored the acid-producing ability of the mutant, providing additional evidence for a role of this two component system in regulating proteolytic activity in L. acidophilus.

scholarly journals Three F-actin assembly centers regulate organelle inheritance, cell-cell communication and motility in Toxoplasma gondii

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Nicolò Tosetti ◽  
Nicolas Dos Santos Pacheco ◽  
Dominique Soldati-Favre ◽  
Damien Jacot
Keyword(s):  
Protein Kinase ◽  
Toxoplasma Gondii ◽  
Actin Polymerization ◽  
Cell Communication ◽  
Residual Body ◽  
Filamentous Actin ◽  
Calcium Dependent ◽  
Actin Regulatory Proteins ◽  
Parasite Motility ◽  
Cell Cell

Toxoplasma gondii possesses a limited set of actin-regulatory proteins and relies on only three formins (FRMs) to nucleate and polymerize actin. We combined filamentous actin (F-actin) chromobodies with gene disruption to assign specific populations of actin filaments to individual formins. FRM2 localizes to the apical juxtanuclear region and participates in apicoplast inheritance. Restricted to the residual body, FRM3 maintains the intravacuolar cell-cell communication. Conoidal FRM1 initiates a flux of F-actin crucial for motility, invasion and egress. This flux depends on myosins A and H and is controlled by phosphorylation via PKG (protein kinase G) and CDPK1 (calcium-dependent protein kinase 1) and by methylation via AKMT (apical lysine methyltransferase). This flux is independent of microneme secretion and persists in the absence of the glideosome-associated connector (GAC). This study offers a coherent model of the key players controlling actin polymerization, stressing the importance of well-timed post-translational modifications to power parasite motility.

scholarly journals A single amino acid substitution (N297A) in the conserved NPXXY sequence of the human N-formyl peptide receptor results in inhibition of desensitization and endocytosis, and a dose-dependent shift in p42/44 mitogen-activated protein kinase activation and chemotaxis

2000 ◽  
Vol 352 (2) ◽  
pp. 399-407 ◽  
Author(s):  
Jeannie M. GRIPENTROG ◽  
Algirdas J. JESAITIS ◽  
Heini M. MIETTINEN
Keyword(s):  
Protein Kinase ◽  
Transmembrane Domain ◽  
Mitogen Activated Protein Kinase ◽  
Formyl Peptide Receptor ◽  
Wild Type ◽  
Peptide Receptor ◽  
Formyl Peptide ◽  
Mitogen Activated Protein ◽  
Dose Dependent Increase ◽  
Dose Dependent

The formyl peptide receptor (FPR) is a G-protein-coupled receptor (GPCR) that mediates chemotaxis and stimulates the mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinase pathway. We have examined the functional effects of substitutions of a conserved aspartic acid residue in the second transmembrane domain (D71A) and of residues in the conserved NPXXY motif in the seventh transmembrane domain (N297A and Y301A). These mutated receptors, expressed in Chinese hamster ovary (CHO) cells, bind ligand with affinities similar to wild-type FPR, but the D71A mutant is uncoupled from G-protein [Miettinen, Mills, Gripentrog, Dratz, Granger and Jesaitis (1997) J. Immunol 159, 4045–4054]. In the present study, we show that both the D71A and N297A mutations resulted in defective endocytosis. The N297A substitution also prevented desensitization, as determined by intracellular calcium mobilization by sequential stimulation with ligand. In chemotaxis assays, the N297A mutation resulted in cell migration towards gradients of up to 100nM N-formyl-methionyl-leucyl-phenylalanine (fMLF), whereas cells expressing the wild-type FPR and the Y301A mutant were no longer chemotactically responsive at 10–100nM fMLF. Maximal activation of p42/44 MAPK occurred in CHO cells expressing wild-type FPR at 10nM–100nM fMLF, whereas cells expressing the N297A mutant showed a dose-dependent increase in the amount of phosphorylated p42/44 MAPK up to 1–10µM fMLF. Since the MAPK kinase inhibitor PD98059 blocked fMLF-induced chemotaxis, our results suggest that the dose-dependent increase in p42/44 MAPK activation may correlate with the increased chemotactic migration of N297A transfectants at 10nM–100nM fMLF.

Investigating the growth performance, meat quality, immune function and proteomic profiles of plasmal exosomes in Lactobacillus plantarum-treated immunosuppressive broilers

2021 ◽  
Author(s):  
Huawei Liu ◽  
Fan Zhao ◽  
Kai Zhang ◽  
Jinshan Zhao ◽  
Yang Wang
Keyword(s):  
Immune Function ◽  
Growth Performance ◽  
Lactobacillus Plantarum ◽  
Meat Quality ◽  
Cell Communication ◽  
Mediate Cell

Exosomes are extracellular membranous nanovesicles that carry functional molecules to mediate cell-to-cell communication. Untile now, whether probiotics improve the immune function of broilers by plasmal exosomal cargo is unclear. In...

The electroneutral cation-chloride cotransporters.

1998 ◽  
Vol 201 (14) ◽  
pp. 2091-2102 ◽  
Author(s):  
D B Mount ◽  
E Delpire ◽  
G Gamba ◽  
A E Hall ◽  
E Poch ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Gene Family ◽  
Molecular Identification ◽  
Membrane Topology ◽  
Cytoplasmic Domains ◽  
Transmembrane Segments ◽  
Novel Gene ◽  
Lower Eukaryotes ◽  
Homologous Genes ◽  
Cation Chloride Cotransporters

Electroneutral cation-chloride cotransporters are widely expressed and perform a variety of physiological roles. A novel gene family of five members, encompassing a Na+-Cl- transporter, two Na+-K+-2Cl- transporters and two K+-Cl- cotransporters, encodes these membrane proteins; homologous genes have also been identified in a prokaryote and a number of lower eukaryotes. The cotransporter proteins share a common predicted membrane topology, with twelve putative transmembrane segments flanked by long hydrophilic N- and C-terminal cytoplasmic domains. The molecular identification of these transporters has had a significant impact on the study of their function, regulation and pathophysiology.

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