Structure and function of the archaeal response regulator CheY

Motility is a central feature of many microorganisms and provides an efficient strategy to respond to environmental changes. Bacteria and archaea have developed fundamentally different rotary motors enabling their motility, termed flagellum and archaellum, respectively. Bacterial motility along chemical gradients, called chemotaxis, critically relies on the response regulator CheY, which, when phosphorylated, inverses the rotational direction of the flagellum via a switch complex at the base of the motor. The structural difference between archaellum and flagellum and the presence of functional CheY in archaea raises the question of how the CheY protein changed to allow communication with the archaeal motility machinery. Here we show that archaeal CheY shares the overall structure and mechanism of magnesium-dependent phosphorylation with its bacterial counterpart. However, bacterial and archaeal CheY differ in the electrostatic potential of the helix α4. The helix α4 is important in bacteria for interaction with the flagellar switch complex, a structure that is absent in archaea. We demonstrated that phosphorylation-dependent activation, and conserved residues in the archaeal CheY helix α4, are important for interaction with the archaeal-specific adaptor protein CheF. This forms a bridge between the chemotaxis system and the archaeal motility machinery. Conclusively, archaeal CheY proteins conserved the central mechanistic features between bacteria and archaea, but differ in the helix α4 to allow binding to an archaellum-specific interaction partner.

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ArlCDE form the archaeal switch complex

10.1101/2020.04.09.033365 ◽

2020 ◽

Author(s):

Zhengqun Li ◽

Marta Rodriguez-Franco ◽

Sonja-Verena Albers ◽

Tessa E. F. Quax

Keyword(s):

Response Regulator ◽

Fluorescent Microscopy ◽

Sensory System ◽

Adaptor Protein ◽

Protein Composition ◽

Directed Movement ◽

Chemical Gradients ◽

Regulator Protein ◽

Chemotaxis System ◽

Response Regulator Protein

Cells require a sensory system and a motility structure to achieve directed movement. Bacteria and archaea both possess rotating filamentous motility structures that work in concert with the sensory chemotaxis system. This allows microorganisms to move along chemical gradients. The central response regulator protein CheY can bind to the motor of the motility structure, the flagellum in bacteria and the archaellum in archaea. Both motility structures have a fundamentally different protein composition and structural organization. Yet, both systems receive input from the chemotaxis system. We applied a fluorescent microscopy approach in the model euryarchaeon Haloferax volcanii, and shed light on the sequence order in which signals are transferred from the chemotaxis system to the archaellum. Our findings indicate that the euryarchaeal specific ArlCDE are part of the archaellum motor and that they directly receive input from the chemotaxis system via the adaptor protein CheF. Hence, ArlCDE are an important feature of the archaellum of euryarchaea, are essential for signal transduction during chemotaxis and represent the archaeal switch complex.

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cAMP-independent control of twitching motility inPseudomonas aeruginosa

10.1101/116954 ◽

2017 ◽

Author(s):

Ryan N.C. Buensuceso ◽

Martin Daniel-Ivad ◽

Sara L.N. Kilmury ◽

Hanjeong Harvey ◽

P. Lynne Howell ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Response Regulator ◽

Opportunistic Pathogen ◽

Regulatory Elements ◽

Twitching Motility ◽

Camp Phosphodiesterase ◽

Polar Localization ◽

And Function ◽

Chemotaxis System ◽

Camp Levels

ABSTRACTFimV is aPseudomonas aeruginosainner membrane hub protein that modulates levels of the second messenger, cyclic AMP (cAMP), through activation of the adenylate cyclase, CyaB. Although type IVa pilus (T4aP)-dependent twitching motility is modulated by cAMP levels, mutants lacking FimV are twitching impaired, even when exogenous cAMP is provided. Here we further define FimV’s cAMP-dependent and -independent regulation of twitching. We confirmed that the response regulator of the T4aP-associated Chp chemotaxis system, PilG, required both FimV and the CyaB regulator, FimL, to activate CyaB. However, in cAMP-replete backgrounds - lacking the cAMP phosphodiesterase CpdA or the CheY-like protein PilH, or expressing constitutively-active CyaB -pilGandfimVmutants failed to twitch. Both cytoplasmic and periplasmic domains of FimV were important for its cAMP-dependent and -independent roles, while its septal peptidoglycan-targeting LysM motif was required only for twitching motility. Polar localization of the sensor kinase PilS, a key regulator of transcription of the major pilin, was FimV-dependent. However, unlike its homologues in other species that localize flagellar system components, FimV was not required for swimming motility. These data provide further evidence to support FimV’s role as a key hub protein that coordinates the polar localization and function of multiple structural and regulatory proteins involved inP. aeruginosatwitching motility.IMPORTANCEPseudomonas aeruginosais a serious opportunistic pathogen. Type IVa pili (T4aP) are important for its virulence, because they mediate dissemination and invasion via twitching motility, and are involved in surface sensing which modulates pathogenicity via changes in cAMP levels. Here we show that the hub protein FimV and the response regulator of the Chp system, PilG, regulate twitching independently of their roles in modulation of cAMP synthesis. These functions do not require the putative scaffold protein FimL, proposed to link PilG with FimV. PilG may regulate asymmetric functioning of the T4aP system to allow for directional movement, while FimV appears to localize both structural and regulatory elements – including the PilSR two-component system – to cell poles for optimal function.

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Effects of Maternal Obesity and Gestational Diabetes Mellitus on the Placenta: Current Knowledge and Targets for Therapeutic Interventions

Current Vascular Pharmacology ◽

10.2174/1570161118666200616144512 ◽

2020 ◽

Vol 19 (2) ◽

pp. 176-192

Author(s):

Samantha Bedell ◽

Janine Hutson ◽

Barbra de Vrijer ◽

Genevieve Eastabrook

Keyword(s):

Diabetes Mellitus ◽

Gestational Diabetes ◽

Gestational Diabetes Mellitus ◽

Maternal Obesity ◽

Environmental Changes ◽

Current Knowledge ◽

Therapeutic Interventions ◽

Placental Development ◽

Exchange Site ◽

And Function

: Obesity and gestational diabetes mellitus (GDM) are becoming more common among pregnant women worldwide and are individually associated with a number of placenta-mediated obstetric complications, including preeclampsia, macrosomia, intrauterine growth restriction and stillbirth. The placenta serves several functions throughout pregnancy and is the main exchange site for the transfer of nutrients and gas from mother to fetus. In pregnancies complicated by maternal obesity or GDM, the placenta is exposed to environmental changes, such as increased inflammation and oxidative stress, dyslipidemia, and altered hormone levels. These changes can affect placental development and function and lead to abnormal fetal growth and development as well as metabolic and cardiovascular abnormalities in the offspring. This review aims to summarize current knowledge on the effects of obesity and GDM on placental development and function. Understanding these processes is key in developing therapeutic interventions with the goal of mitigating these effects and preventing future cardiovascular and metabolic pathology in subsequent generations.

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Structure and dynamics of the E. coli chemotaxis core signaling complex by cryo-electron tomography and molecular simulations

Communications Biology ◽

10.1038/s42003-019-0748-0 ◽

2020 ◽

Vol 3 (1) ◽

Cited By ~ 8

Author(s):

C. Keith Cassidy ◽

Benjamin A. Himes ◽

Dapeng Sun ◽

Jun Ma ◽

Gongpu Zhao ◽

...

Keyword(s):

Molecular Mechanisms ◽

Electron Tomography ◽

Conformational Dynamics ◽

Molecular Simulations ◽

Adaptor Protein ◽

Signaling Mechanism ◽

E Coli ◽

Signaling Complex ◽

Chemical Gradients ◽

Cryo Electron Tomography

AbstractTo enable the processing of chemical gradients, chemotactic bacteria possess large arrays of transmembrane chemoreceptors, the histidine kinase CheA, and the adaptor protein CheW, organized as coupled core-signaling units (CSU). Despite decades of study, important questions surrounding the molecular mechanisms of sensory signal transduction remain unresolved, owing especially to the lack of a high-resolution CSU structure. Here, we use cryo-electron tomography and sub-tomogram averaging to determine a structure of the Escherichia coli CSU at sub-nanometer resolution. Based on our experimental data, we use molecular simulations to construct an atomistic model of the CSU, enabling a detailed characterization of CheA conformational dynamics in its native structural context. We identify multiple, distinct conformations of the critical P4 domain as well as asymmetries in the localization of the P3 bundle, offering several novel insights into the CheA signaling mechanism.

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The Ubiquitously Expressed Csk Adaptor Protein Cbp Is Dispensable for Embryogenesis and T-Cell Development and Function

Molecular and Cellular Biology ◽

10.1128/mcb.25.23.10533-10542.2005 ◽

2005 ◽

Vol 25 (23) ◽

pp. 10533-10542 ◽

Cited By ~ 59

Author(s):

Marc-Werner Dobenecker ◽

Christian Schmedt ◽

Masato Okada ◽

Alexander Tarakhovsky

Keyword(s):

T Cell ◽

Adaptor Protein ◽

Regulatory Function ◽

Loss Of Function ◽

Thymic Development ◽

Cell Functions ◽

Carboxy Terminal ◽

And Function

ABSTRACT Regulation of Src family kinase (SFK) activity is indispensable for a functional immune system and embryogenesis. The activity of SFKs is inhibited by the presence of the carboxy-terminal Src kinase (Csk) at the cell membrane. Thus, recruitment of cytosolic Csk to the membrane-associated SFKs is crucial for its regulatory function. Previous studies utilizing in vitro and transgenic models suggested that the Csk-binding protein (Cbp), also known as phosphoprotein associated with glycosphingolipid microdomains (PAG), is the membrane adaptor for Csk. However, loss-of-function genetic evidence to support this notion was lacking. Herein, we demonstrate that the targeted disruption of the cbp gene in mice has no effect on embryogenesis, thymic development, or T-cell functions in vivo. Moreover, recruitment of Csk to the specialized membrane compartment of “lipid rafts” is not impaired by Cbp deficiency. Our results indicate that Cbp is dispensable for the recruitment of Csk to the membrane and that another Csk adaptor, yet to be discovered, compensates for the loss of Cbp.

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The transmembrane adaptor protein NTAL limits mast cell chemotaxis toward prostaglandin E2

Science Signaling ◽

10.1126/scisignal.aao4354 ◽

2018 ◽

Vol 11 (556) ◽

pp. eaao4354 ◽

Cited By ~ 1

Author(s):

Ivana Halova ◽

Monika Bambouskova ◽

Lubica Draberova ◽

Viktor Bugajev ◽

Petr Draber

Keyword(s):

Mast Cell ◽

Mast Cells ◽

T Cell Activation ◽

Cell Activation ◽

Adaptor Protein ◽

Prostaglandin E ◽

Dependent Manner ◽

And Function ◽

Cell Chemotaxis

Chemotaxis of mast cells is one of the crucial steps in their development and function. Non–T cell activation linker (NTAL) is a transmembrane adaptor protein that inhibits the activation of mast cells and B cells in a phosphorylation-dependent manner. Here, we studied the role of NTAL in the migration of mouse mast cells stimulated by prostaglandin E2 (PGE2). Although PGE2 does not induce the tyrosine phosphorylation of NTAL, unlike IgE immune complex antigens, we found that loss of NTAL increased the chemotaxis of mast cells toward PGE2. Stimulation of mast cells that lacked NTAL with PGE2 enhanced the phosphorylation of AKT and the production of phosphatidylinositol 3,4,5-trisphosphate. In resting NTAL-deficient mast cells, phosphorylation of an inhibitory threonine in ERM family proteins accompanied increased activation of β1-containing integrins, which are features often associated with increased invasiveness in tumors. Rescue experiments indicated that only full-length, wild-type NTAL restored the chemotaxis of NTAL-deficient cells toward PGE2. Together, these data suggest that NTAL is a key inhibitor of mast cell chemotaxis toward PGE2, which may act through the RHOA/ERM/β1-integrin and PI3K/AKT axes.

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Molecular basis for Ras suppressor-1 recruitment to focal adhesions and stabilization of consensus adhesome complex

10.1101/2021.02.19.432017 ◽

2021 ◽

Author(s):

Koichi Fukuda ◽

Fan Lu ◽

Jun Qin

Keyword(s):

Cell Adhesion ◽

Focal Adhesion ◽

Specific Interaction ◽

Tumor Development ◽

Focal Adhesions ◽

Adaptor Protein ◽

Biological Data ◽

Structural Basis ◽

Lim Domain ◽

Insight Into

AbstractRas suppressor-1 (Rsu-1) is a leucine-rich repeat (LRR)-containing protein that is crucial for regulating fundamental cell adhesion processes and tumor development. Rsu-1 interacts with a zinc-finger type multi LIM domain-containing adaptor protein PINCH-1 involved in the integrin-mediated consensus adhesome but not with highly homologous isoform PINCH-2. However, the structural basis for such specific interaction and regulatory mechanism remains unclear. Here, we determined the crystal structures of Rsu-1 and its complex with the PINCH-1 LIM4-5 domains. Rsu-1 displays an arc-shaped solenoid architecture with eight LRRs shielded by the N- and C-terminal capping modules. We show that a large conserved concave surface of the Rsu-1 LRR domain recognizes the PINCH-1 LIM5 domain, and that the C-terminal non-LIM region of PINCH-2 but not PINCH-1 sterically disfavors the Rsu-1 binding. We further show that Rsu-1 can be assembled, via PINCH-1-binding, into a tight hetero-pentamer complex comprising Rsu-1, PINCH-1, ILK, Parvin, and Kindlin-2 that constitute a major consensus integrin adhesome crucial for focal adhesion assembly. Consistently, our mutagenesis and cell biological data consolidate the significance of the Rsu-1/PINCH-1 interaction in focal adhesion assembly and cell spreading. Our results provide a crucial molecular insight into Rsu-1-mediated cell adhesion with implication on how it may regulate tumorigenic growth.

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The Meaning and Function of Ritual in Psychiatric Disorder, Religion and Everyday Behaviour

Australian & New Zealand Journal of Psychiatry ◽

10.3109/00048679709065509 ◽

1997 ◽

Vol 31 (6) ◽

pp. 835-843 ◽

Cited By ~ 9

Author(s):

John Turbott

Keyword(s):

Obsessive Compulsive Disorder ◽

Religious Studies ◽

Central Feature ◽

Obsessive Compulsive ◽

Compulsive Disorder ◽

Clinical Orientation ◽

Psychiatric Conditions ◽

Biopsychosocial Perspective ◽

And Function ◽

Meaning And Function

Objective: Ritual is a central feature of obsessive-compulsive disorder (OCD) and is found in other psychiatric conditions. Defined in a general sense, it is seen in the everyday behaviour of animals and of humans, in secular ceremonies, and in religion. This paper examines the various types of ritual. It considers the common features and differences. Method: Material from psychiatric, biological, sociological, anthropological and religious studies literature is reviewed and discussed. Results: The term ‘ritual’ describes a wide variety of phenomena. These include the rituals of OCD and range from relatively simple animal signals to profoundly meaningful human behaviour. A common feature is stereotyped physical activity which conveys information. Some clinical, developmental, evolutionary and religioud historical evidence suggests that stereotyped motor behaviour may be the primary phenomenon. Conclusions: The study of ritual in all its manifestations provides insight into the basis of important human behaviours. Obsessive-compulsive disorder is a likely paradigm for this study. Psychiatry, with its clinical orientation and biopsychosocial perspective, is a discipline within which the study might occur.

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Evidence for a novel antioxidant function and isoform-specific regulation of the human p66Shc gene

Molecular Biology of the Cell ◽

10.1091/mbc.e13-11-0666 ◽

2014 ◽

Vol 25 (13) ◽

pp. 2116-2127 ◽

Cited By ~ 22

Author(s):

Masaki Miyazawa ◽

Yoshiaki Tsuji

Keyword(s):

Stress Response ◽

Adaptor Protein ◽

Erythroid Differentiation ◽

Cell Types ◽

Antioxidant Response ◽

Related Factor ◽

Antioxidant Genes ◽

Specific Regulation ◽

And Function ◽

Species Production

The mammalian Shc family, composed of p46, p52, and p66 isoforms, serves as an adaptor protein in cell growth and stress response. p66Shc was shown to be a negative lifespan regulator by acting as a prooxidant protein in mitochondria; however, the regulatory mechanisms of p66Shc expression and function are incompletely understood. This study provides evidence for new features of p66Shc serving as an antioxidant and critical protein in cell differentiation. Unique among the Shc family, transcription of p66Shc is activated through the antioxidant response element (ARE)–nuclear factor erythroid 2–related factor 2 (Nrf2) pathway in K562 human erythroleukemia and other cell types after treatment with hemin, an iron-containing porphyrin. Phosphorylated p66Shc at Ser-36, previously reported to be prone to mitochondrial localization, is increased by hemin treatment, but p66Shc remains exclusively in the cytoplasm. p66Shc knockdown inhibits hemin-induced erythroid differentiation, in which reactive oxygen species production and apoptosis are significantly enhanced in conjunction with suppression of other ARE-dependent antioxidant genes. Conversely, p66Shc overexpression is sufficient for inducing erythroid differentiation. Collectively these results demonstrate the isoform-specific regulation of the Shc gene by the Nrf2-ARE pathway and a new antioxidant role of p66Shc in the cytoplasm. Thus p66Shc is a bifunctional protein involved in cellular oxidative stress response and differentiation.

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Regulation of Clathrin-Mediated Endocytosis

Annual Review of Biochemistry ◽

10.1146/annurev-biochem-062917-012644 ◽

2018 ◽

Vol 87 (1) ◽

pp. 871-896 ◽

Cited By ~ 108

Author(s):

Marcel Mettlen ◽

Ping-Hung Chen ◽

Saipraveen Srinivasan ◽

Gaudenz Danuser ◽

Sandra L. Schmid

Keyword(s):

Conformational Changes ◽

Posttranslational Modifications ◽

Mammalian Cells ◽

Environmental Changes ◽

Protein Complexes ◽

Adaptor Protein ◽

Endocytic Pathway ◽

Coat Proteins ◽

Membrane Composition ◽

Coated Pits

Clathrin-mediated endocytosis (CME) is the major endocytic pathway in mammalian cells. It is responsible for the uptake of transmembrane receptors and transporters, for remodeling plasma membrane composition in response to environmental changes, and for regulating cell surface signaling. CME occurs via the assembly and maturation of clathrin-coated pits that concentrate cargo as they invaginate and pinch off to form clathrin-coated vesicles. In addition to the major coat proteins, clathrin triskelia and adaptor protein complexes, CME requires a myriad of endocytic accessory proteins and phosphatidylinositol lipids. CME is regulated at multiple steps—initiation, cargo selection, maturation, and fission—and is monitored by an endocytic checkpoint that induces disassembly of defective pits. Regulation occurs via posttranslational modifications, allosteric conformational changes, and isoform and splice-variant differences among components of the CME machinery, including the GTPase dynamin. This review summarizes recent findings on the regulation of CME and the evolution of this complex process.

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