scholarly journals Simulation of intra‐ciliary diffusion suggests a novel role of primary cilia as a cell‐signaling enhancer

2017 ◽  
Vol 59 (5) ◽  
pp. 415-422 ◽  
Author(s):  
Daisuke Takao ◽  
Shinji Kamimura
Keyword(s):  
Cell Signaling ◽  
Primary Cilia ◽  
A Cell

Protein Flexibility Catalyzes a Cell Signaling Reaction of the Ras-GAP Complex

2019 ◽  
Author(s):  
Keiei Kumon ◽  
Masahiro Higashi ◽  
Shinji Saito ◽  
Shigehiko Hayashi
Keyword(s):  
Cell Signaling ◽  
Conformational Changes ◽  
Catalytic Reaction ◽  
Protein Complex ◽  
Enzyme Mechanism ◽  
Activation Free Energy ◽  
Chemical Catalysis ◽  
Simple Chemical ◽  
A Cell ◽  
Enzyme Molecules

Many enzyme molecules exhibit characteristic global and slow dynamics which furnish them with allostery realizing remarkable molecular functionalities more than simple chemical catalysis. However, molecular mechanism of a catalytic reaction associated with the molecular flexibility of enzymes is not well-understood. Here we report a hybrid molecular simulation study on GTPase activity of a Ras-GAP protein complex for cell signaling termination. We unveiled that extensive conformational changes of the protein complex and exclusion of internal water molecules are induced upon the transition state (TS) formation in the catalytic reaction and significantly lower the reaction activation free energy. We also revealed that tumor-related mutations perturb those conformational changes upon the TS formation, leading to reduction of the catalytic activity. The findings of the remarkably dynamic protein conformation directly linking to the catalytic reaction have broad implications for understanding of enzyme mechanism and for developments of allosteric drugs and novel catalysts.

CD38 as an immunomodulator in cancer

2020 ◽  
Vol 16 (34) ◽  
pp. 2853-2861
Author(s):  
Yanli Li ◽  
Rui Yang ◽  
Limo Chen ◽  
Sufang Wu
Keyword(s):  
Multiple Myeloma ◽  
Cell Activation ◽  
Human Tissues ◽  
Transmembrane Glycoprotein ◽  
Cell Activation Marker ◽  
Research Findings ◽  
A Cell ◽  
And Function ◽  
Human Molecule

CD38 is a transmembrane glycoprotein that is widely expressed in a variety of human tissues and cells, especially those in the immune system. CD38 protein was previously considered as a cell activation marker, and today monoclonal antibodies targeting CD38 have witnessed great achievements in multiple myeloma and promoted researchers to conduct research on other tumors. In this review, we provide a wide-ranging review of the biology and function of the human molecule outside the field of myeloma. We focus mainly on current research findings to summarize and update the findings gathered from diverse areas of study. Based on these findings, we attempt to extend the role of CD38 in the context of therapy of solid tumors and expand the role of the molecule from a simple marker to an immunomodulator.

scholarly journals PapRIV, a BV-2 microglial cell activating quorum sensing peptide

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yorick Janssens ◽  
Nathan Debunne ◽  
Anton De Spiegeleer ◽  
Evelien Wynendaele ◽  
Marta Planas ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Cell Model ◽  
Dependent Manner ◽  
Communication Signals ◽  
Gram Positive Bacteria ◽  
A Cell ◽  
Gastro Intestinal Tract

AbstractQuorum sensing peptides (QSPs) are bacterial peptides produced by Gram-positive bacteria to communicate with their peers in a cell-density dependent manner. These peptides do not only act as interbacterial communication signals, but can also have effects on the host. Compelling evidence demonstrates the presence of a gut-brain axis and more specifically, the role of the gut microbiota in microglial functioning. The aim of this study is to investigate microglial activating properties of a selected QSP (PapRIV) which is produced by Bacillus cereus species. PapRIV showed in vitro activating properties of BV-2 microglia cells and was able to cross the in vitro Caco-2 cell model and reach the brain. In vivo peptide presence was also demonstrated in mouse plasma. The peptide caused induction of IL-6, TNFα and ROS expression and increased the fraction of ameboid BV-2 microglia cells in an NF-κB dependent manner. Different metabolites were identified in serum, of which the main metabolite still remained active. PapRIV is thus able to cross the gastro-intestinal tract and the blood–brain barrier and shows in vitro activating properties in BV-2 microglia cells, hereby indicating a potential role of this quorum sensing peptide in gut-brain interaction.

scholarly journals Centrin2 regulates CP110 removal in primary cilium formation

2015 ◽  
Vol 208 (6) ◽  
pp. 693-701 ◽  
Author(s):  
Suzanna L. Prosser ◽  
Ciaran G. Morrison
Keyword(s):  
Calcium Binding ◽  
Primary Cilia ◽  
Reverse Genetics ◽  
Cell Types ◽  
Serum Starvation ◽  
Basal Bodies ◽  
Cilium Formation ◽  
Cellular Quiescence ◽  
Retinal Pigmented Epithelial Cells

Primary cilia are antenna-like sensory microtubule structures that extend from basal bodies, plasma membrane–docked mother centrioles. Cellular quiescence potentiates ciliogenesis, but the regulation of basal body formation is not fully understood. We used reverse genetics to test the role of the small calcium-binding protein, centrin2, in ciliogenesis. Primary cilia arise in most cell types but have not been described in lymphocytes. We show here that serum starvation of transformed, cultured B and T cells caused primary ciliogenesis. Efficient ciliogenesis in chicken DT40 B lymphocytes required centrin2. We disrupted CETN2 in human retinal pigmented epithelial cells, and despite having intact centrioles, they were unable to make cilia upon serum starvation, showing abnormal localization of distal appendage proteins and failing to remove the ciliation inhibitor CP110. Knockdown of CP110 rescued ciliation in CETN2-deficient cells. Thus, centrin2 regulates primary ciliogenesis through controlling CP110 levels.

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