Septins as key regulators of actin based processes in bacterial infection

Abstract Many pathogens have evolved a variety of mechanisms to exploit the host-cell actin cytoskeleton during infection, either to enter into cells or to move within cells. These events have been investigated and documented in detail. Yet, a complete picture of the molecules and mechanisms regulating entry and intracellular movement remains to be established. Here we present a series of studies revealing that in addition to actin rearrangements the host cell also employs septins, a relatively newly characterized component of the cell cyto-skeleton, to regulate bacterial entry and restrict the dissemination of cytosolic bacteria. The challenge now is to decipher the precise role of septins during actin rearrangements and how these different cytoskeleton components orchestrate infection processes.

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ARP2/3-Mediated Actin Nucleation Associated With Symbiosome Membrane Is Essential for the Development of Symbiosomes in Infected Cells of Medicago truncatula Root Nodules

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-12-14-0402-r ◽

2015 ◽

Vol 28 (5) ◽

pp. 605-614 ◽

Cited By ~ 25

Author(s):

Aleksandr Gavrin ◽

Veerle Jansen ◽

Sergey Ivanov ◽

Ton Bisseling ◽

Elena Fedorova

Keyword(s):

Actin Cytoskeleton ◽

Host Cell ◽

Medicago Truncatula ◽

Root Nodules ◽

Nitrogen Fixing ◽

Actin Networks ◽

Cell Plasma ◽

Membrane Compartments ◽

Infected Cells

The nitrogen-fixing rhizobia in the symbiotic infected cells of root nodules are kept in membrane compartments derived from the host cell plasma membrane, forming what are known as symbiosomes. These are maintained as individual units, with mature symbiosomes having a specific radial position in the host cell cytoplasm. The mechanisms that adapt the host cell architecture to accommodate intracellular bacteria are not clear. The intracellular organization of any cell depends heavily on the actin cytoskeleton. Dynamic rearrangement of the actin cytoskeleton is crucial for cytoplasm organization and intracellular trafficking of vesicles and organelles. A key component of the actin cytoskeleton rearrangement is the ARP2/3 complex, which nucleates new actin filaments and forms branched actin networks. To clarify the role of the ARP2/3 complex in the development of infected cells and symbiosomes, we analyzed the pattern of actin microfilaments and the functional role of ARP3 in Medicago truncatula root nodules. In infected cells, ARP3 protein and actin were spatially associated with maturing symbiosomes. Partial ARP3 silencing causes defects in symbiosome development; in particular, ARP3 silencing disrupts the final differentiation steps in functional maturation into nitrogen-fixing units.

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Host-cell-dependent role of actin cytoskeleton during the replication of a human strain of influenza A virus

Archives of Virology ◽

10.1007/s00705-008-0103-0 ◽

2008 ◽

Vol 153 (7) ◽

pp. 1209-1221 ◽

Cited By ~ 17

Author(s):

M. C. Arcangeletti ◽

F. De Conto ◽

F. Ferraglia ◽

F. Pinardi ◽

R. Gatti ◽

...

Keyword(s):

Actin Cytoskeleton ◽

Host Cell ◽

Influenza A Virus ◽

Influenza A ◽

Human Strain

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E6 and E7 oncoproteins: Potential targets of cervical cancer

Current Medicinal Chemistry ◽

10.2174/0929867327666201111145546 ◽

2020 ◽

Vol 27 ◽

Author(s):

Ramarao Malla ◽

Mohammad Amjad Kamal

Keyword(s):

Cervical Cancer ◽

Drug Resistance ◽

Host Cell ◽

Molecular Mechanisms ◽

Immune Therapy ◽

Cervical Lesions ◽

Diagnostic Strategies ◽

E6 And E7 Oncoproteins ◽

E6 And E7

: Cervical cancer (CC) is the fourth leading cancer in women in the age group 15-44 globally. Experimental as well as epidemiological studies identified that type16 and 18 HPV cause 70% of precancerous cervical lesions as well as cervical cancer worldwide by bringing about genetic as well as epigenetic changes in the host genome. The insertion of the HPV genome triggers various defense mechanisms including the silencing of tumor suppressor genes as well as activation of oncogenes associated with cancer metastatic pathway. E6 and E7 are small oncoproteins consisting of 150 and 100 amino acids respectively. These oncoproteins affect the regulation of the host cell cycle by interfering with p53 and pRb. Further these oncoproteins adversely affect the normal functions of the host cell by binding to their signaling proteins. Recent studies demonstrated that E6 and E7 oncoproteins are potential targets for CC. Therefore, this review discusses the role of E6 and E7 oncoproteins in metastasis and drug resistance as well as their regulation, early oncogene mediated signaling pathways. This review also uncovers the recent updates on molecular mechanisms of E6 and E7 mediated phytotherapy, gene therapy, immune therapy, and vaccine strategies as well as diagnosis through precision testing. Therefore, understanding the potential role of E6/E7 in metastasis and drug resistance along with targeted treatment, vaccine, and precision diagnostic strategies could be useful for the prevention and treatment of cervical cancer.

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Membrane Homeostasis: The Role of Actin Cytoskeleton

Journal of the Indian Institute of Science ◽

10.1007/s41745-020-00217-x ◽

2021 ◽

Vol 101 (1) ◽

pp. 81-95

Author(s):

Arikta Biswas ◽

Rinku Kumar ◽

Bidisha Sinha

Keyword(s):

Actin Cytoskeleton

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Cholinergic Signaling, Neural Excitability, and Epilepsy

Molecules ◽

10.3390/molecules26082258 ◽

2021 ◽

Vol 26 (8) ◽

pp. 2258

Author(s):

Yu Wang ◽

Bei Tan ◽

Yi Wang ◽

Zhong Chen

Keyword(s):

Cholinergic Neurons ◽

Epileptic Seizures ◽

Brain Disorder ◽

Neural Excitability ◽

Cholinergic Signaling ◽

The Central Nervous System ◽

Muscarinic And Nicotinic Receptors ◽

Cumulative Evidence ◽

Precise Role

Epilepsy is a common brain disorder characterized by recurrent epileptic seizures with neuronal hyperexcitability. Apart from the classical imbalance between excitatory glutamatergic transmission and inhibitory γ-aminobutyric acidergic transmission, cumulative evidence suggest that cholinergic signaling is crucially involved in the modulation of neural excitability and epilepsy. In this review, we briefly describe the distribution of cholinergic neurons, muscarinic, and nicotinic receptors in the central nervous system and their relationship with neural excitability. Then, we summarize the findings from experimental and clinical research on the role of cholinergic signaling in epilepsy. Furthermore, we provide some perspectives on future investigation to reveal the precise role of the cholinergic system in epilepsy.

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I-102 Viral fitness costs and benefits of disrupting the host cell actin cytoskeleton in mucosal HIV-infection

JAIDS Journal of Acquired Immune Deficiency Syndromes ◽

10.1097/01.qai.0000557988.95699.8e ◽

2019 ◽

Vol 81 ◽

pp. 49

Author(s):

Thorsten Mempel ◽

Shariq Usmani ◽

Thomas Murooka

Keyword(s):

Hiv Infection ◽

Actin Cytoskeleton ◽

Host Cell ◽

Viral Fitness ◽

Costs And Benefits ◽

Fitness Costs

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The Constitutive Centromere Component CENP-50 Is Required for Recovery from Spindle Damage

Molecular and Cellular Biology ◽

10.1128/mcb.25.23.10315-10328.2005 ◽

2005 ◽

Vol 25 (23) ◽

pp. 10315-10328 ◽

Cited By ~ 54

Author(s):

Yukinori Minoshima ◽

Tetsuya Hori ◽

Masahiro Okada ◽

Hiroshi Kimura ◽

Tokuko Haraguchi ◽

...

Keyword(s):

Cell Cycle ◽

Growth Rate ◽

Mitotic Checkpoint ◽

Loss Of Function ◽

Wild Type ◽

Centromere Function ◽

Dt40 Cells ◽

Precise Role ◽

Chicken Dt40 Cell

ABSTRACT We identified CENP-50 as a novel kinetochore component. We found that CENP-50 is a constitutive component of the centromere that colocalizes with CENP-A and CENP-H throughout the cell cycle in vertebrate cells. To determine the precise role of CENP-50, we examined its role in centromere function by generating a loss-of-function mutant in the chicken DT40 cell line. The CENP-50 knockout was not lethal; however, the growth rate of cells with this mutation was slower than that of wild-type cells. We observed that the time for CENP-50-deficient cells to complete mitosis was longer than that for wild-type cells. Centromeric localization of CENP-50 was abolished in both CENP-H- and CENP-I-deficient cells. Coimmunoprecipitation experiments revealed that CENP-50 interacted with the CENP-H/CENP-I complex in chicken DT40 cells. We also observed severe mitotic defects in CENP-50-deficient cells with apparent premature sister chromatid separation when the mitotic checkpoint was activated, indicating that CENP-50 is required for recovery from spindle damage.

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