scholarly journals An ABC Transporter Plays a Developmental Aggregation Role in Myxococcus xanthus

1998 ◽  
Vol 180 (21) ◽  
pp. 5697-5703 ◽  
Author(s):  
Mandy J. Ward ◽  
Kenny C. Mok ◽  
David P. Astling ◽  
Helen Lew ◽  
David R. Zusman
Keyword(s):  
Signal Transduction ◽  
Life Cycle ◽  
Abc Transporter ◽  
Response Regulator ◽  
Myxococcus Xanthus ◽  
Complex Life Cycle ◽  
Upstream Region ◽  
Atp Binding ◽  
Cloning And Sequencing ◽  
Atp Binding Cassette

ABSTRACT Myxococcus xanthus is a gram-negative bacterium which has a complex life cycle. Autochemotaxis, a process whereby cells release a self-generated signaling molecule, may be the principal mechanism facilitating directed motility in both the vegetative swarming and developmental aggregation stages of this life cycle. The process requires the Frz signal transduction system, including FrzZ, a protein which is composed of two domains, both showing homology to the enteric chemotaxis response regulator CheY. The first domain of FrzZ (FrzZ1), when expressed as bait in the yeast two-hybrid system and screened against a library, was shown to potentially interact with the C-terminal portion of a protein encoding an ATP-binding cassette (AbcA). The activation domain-AbcA fusion protein did not interact with the second domain of FrzZ (FrzZ2) or with two other M. xanthus response regulator-containing proteins presented as bait, suggesting that the FrzZ1-AbcA interaction may be specific. Cloning and sequencing of the upstream region of the abcA gene showed the ATP-binding cassette to be linked to a large hydrophobic, potentially membrane-spanning domain. This domain organization is characteristic of a subgroup of ABC transporters which perform export functions. Cloning and sequencing downstream of abcAindicated that the ABC transporter is at the start of an operon containing three open reading frames. An insertion mutation in theabcA gene resulted in cells displaying the frizzy aggregation phenotype, providing additional evidence that FrzZ and AbcA may be part of the same signal transduction pathway. Cells with mutations in genes downstream of abcA showed no developmental defects. Analysis of the proposed exporter role of AbcA in cell mixing experiments showed that the ABC transporter mutant could be rescued by extracellular complementation. We speculate that the AbcA protein may be involved in the export of a molecule required for the autochemotactic process.

scholarly journals Myxococcus xanthus Displays Frz-Dependent Chemokinetic Behavior during Vegetative Swarming

1998 ◽  
Vol 180 (2) ◽  
pp. 440-443 ◽  
Author(s):  
Mandy J. Ward ◽  
Kenny C. Mok ◽  
David R. Zusman
Keyword(s):  
Signal Transduction ◽  
Life Cycle ◽  
Cell Density ◽  
Myxococcus Xanthus ◽  
Microscopic Analysis ◽  
Time Lapse ◽  
Complex Life Cycle ◽  
Signal Transduction System ◽  
Nutrient Levels ◽  
Time Lapse Video

ABSTRACT Myxococcus xanthus has been shown to utilize both directed (tactic) and undirected (kinetic) movements during different stages of its complex life cycle. We have used time-lapse video microscopic analysis to separate tactic and kinetic behaviors associated specifically with vegetatively swarming cells. Isolated individual cells separated by a thin agar barrier from mature swarms showed significant increases in gliding velocity compared to that of similar cells some distance from the swarm. This orthokinetic behavior was independent of the frequency of reversals of gliding direction (klinokinesis) but did require both the Frz signal transduction system and S-motility. We propose that M. xanthus uses Frz-dependent, auto-orthokinetic behavior to facilitate the dispersal of cells under conditions where both cell density and nutrient levels are high.

scholarly journals Regulation of Motility Behavior in Myxococcus xanthus May Require an Extracytoplasmic-Function Sigma Factor

1998 ◽  
Vol 180 (21) ◽  
pp. 5668-5675 ◽  
Author(s):  
Mandy J. Ward ◽  
Helen Lew ◽  
Anke Treuner-Lange ◽  
David R. Zusman
Keyword(s):  
Life Cycle ◽  
Sigma Factor ◽  
Response Regulator ◽  
Myxococcus Xanthus ◽  
Complex Life Cycle ◽  
Insertion Mutant ◽  
Insertion Mutation ◽  
Ecf Sigma Factor ◽  
Developmental Conditions ◽  
Motility Behavior

ABSTRACT Using interaction trap technology, we identified a putative extracytoplasmic-function (ECF) sigma factor (RpoE1) inMyxococcus xanthus, a bacterium which has a complex life cycle that includes fruiting body formation. The first domain of the response regulator protein FrzZ, a component of the Frz signal transduction system, was used as bait. Although the RpoE1 protein displayed no interactions with control proteins presented as bait, a weak interaction with a second M. xanthus response regulator (AsgA) was observed. While the specificity of the FrzZ-RpoE1 interaction therefore remains speculative, cloning and sequencing of the region surrounding rpoE1 localized it to a position downstream of the frzZ gene. A potential promoter site for binding of an ECF sigma factor was identified upstream ofrpoE1, suggesting the gene may be autoregulated. However, primer extension studies suggested that transcription ofrpoE1 occurs under both vegetative and developmental conditions from a ς70-like promoter. Dot blot analysis of RNA preparations confirmed the low-level, constitutive expression ofrpoE1 during both stages of the life cycle. Analysis of an insertion mutant also indicated a role for RpoE1 under both vegetative and developmental conditions, since swarming was reduced on nutrient-rich agar and developmental aggregation was effected under starvation conditions, especially at high cell densities. An insertion mutation introduced into the gene directly downstream ofrpoE1 (orf5) did not result in either swarming or developmental aggregation defects, even though the gene is transcribed as part of the same operon. Therefore, we propose that this new ECF sigma factor could play a role in the transcriptional regulation of genes involved in motility behavior during both stages of the complex M. xanthus life cycle.

scholarly journals The human ATP-binding cassette (ABC) transporter superfamily

2001 ◽  
Vol 42 (7) ◽  
pp. 1007-1017 ◽  
Author(s):  
Michael Dean ◽  
Yannick Hamon ◽  
Giovanna Chimini
Keyword(s):  
Abc Transporter ◽  
Atp Binding ◽  
Atp Binding Cassette

scholarly journals Nucleotide-dependent Allostery within the ABC Transporter ATP-binding Cassette

2007 ◽  
Vol 282 (31) ◽  
pp. 22793-22803 ◽  
Author(s):  
Peter M. Jones ◽  
Anthony M. George
Keyword(s):  
Abc Transporter ◽  
Atp Binding ◽  
Atp Binding Cassette

scholarly journals ATP Binding Cassette Transporter A1 is Involved in Extracellular Secretion of Acetylated APE1/Ref-1

2019 ◽  
Vol 20 (13) ◽  
pp. 3178 ◽  
Author(s):  
Yu Ran Lee ◽  
Hee Kyoung Joo ◽  
Eun Ok Lee ◽  
Hyun Sil Cho ◽  
Sunga Choi ◽  
...  
Keyword(s):  
Abc Transporter ◽  
Abc Transporters ◽  
Secretory Pathway ◽  
Trichostatin A ◽  
Atp Binding ◽  
Terminal Protein ◽  
Secretion Signal ◽  
Extracellular Secretion ◽  
Atp Binding Cassette Transporter ◽  
Atp Binding Cassette

Acetylation of nuclear apurinic/apyrimidinic endonuclease-1/redox factor-1 (APE1/Ref-1) is associated with its extracellular secretion, despite the lack of an N-terminal protein secretion signal. In this study, we investigated plasma membrane targeting and translocation of APE1/Ref-1 in HEK293T cells with enhanced acetylation. While APE1/Ref-1 targeting was not affected by inhibition of the endoplasmic reticulum/Golgi-dependent secretion, its secretion was reduced by inhibitors of ATP-binding cassette (ABC) transporters, and siRNA-mediated down-regulation of ABC transporter A1. The association between APE1/Ref-1 and ABCA1 transporter was confirmed by proximal ligation assay and immunoprecipitation experiments. An APE1/Ref-1 construct with mutated acetylation sites (K6/K7R) showed reduced co-localization with ABC transporter A1. Exposure of trichostatin A (TSA) induced the acetylation of APE1/Ref-1, which translocated into membrane fraction. Taken together, acetylation of APE1/Ref-1 is considered to be necessary for its extracellular targeting via non-classical secretory pathway using the ABCA1 transporter.

scholarly journals Cystathionine β-Synthase (CBS) Domains 1 and 2 Fulfill Different Roles in Ionic Strength Sensing of the ATP-binding Cassette (ABC) Transporter OpuA

2011 ◽  
Vol 286 (43) ◽  
pp. 37280-37291 ◽  
Author(s):  
Akira Karasawa ◽  
Guus B. Erkens ◽  
Ronnie P.-A. Berntsson ◽  
Renee Otten ◽  
Gea K. Schuurman-Wolters ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Abc Transporter ◽  
Atp Binding ◽  
Cbs Domains ◽  
Atp Binding Cassette

scholarly journals Mutations that alter the transmembrane signalling pathway in an ATP binding cassette (ABC) transporter.

1994 ◽  
Vol 13 (7) ◽  
pp. 1752-1759 ◽  
Author(s):  
K.M. Covitz ◽  
C.H. Panagiotidis ◽  
L.I. Hor ◽  
M. Reyes ◽  
N.A. Treptow ◽  
...  
Keyword(s):  
Abc Transporter ◽  
Signalling Pathway ◽  
Atp Binding ◽  
Transmembrane Signalling ◽  
Atp Binding Cassette
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