Cells

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Open AccessArticle

A Phospho-SIM in the Antiviral Protein PML is Required for Its Recruitment to HSV-1 Genomes

by Miles C. Smith, Andrew C. Box, Jeffrey S. Haug, William S. Lane and David J. Davido

Cells 2014, 3(4), 1131-1158; https://doi.org/10.3390/cells3041131 - 10 Dec 2014

Cited by 2 | Viewed by 8527

Herpes simplex virus type 1 (HSV-1) is a significant human pathogen that infects a large portion of the human population. Cells deploy a variety of defenses to limit the extent to which the virus can replicate. One such factor is the promyelocytic leukemia [...] Read more.

Herpes simplex virus type 1 (HSV-1) is a significant human pathogen that infects a large portion of the human population. Cells deploy a variety of defenses to limit the extent to which the virus can replicate. One such factor is the promyelocytic leukemia (PML) protein, the nucleating and organizing factor of nuclear domain 10 (ND10). PML responds to a number of stimuli and is implicated in intrinsic and innate cellular antiviral defenses against HSV-1. While the role of PML in a number of cellular pathways is controlled by post-translational modifications, the effects of phosphorylation on its antiviral activity toward HSV-1 have been largely unexplored. Consequently, we mapped phosphorylation sites on PML, mutated these and other known phosphorylation sites on PML isoform I (PML-I), and examined their effects on a number of PML’s activities. Our results show that phosphorylation at most sites on PML-I is dispensable for the formation of ND10s and colocalization between PML-I and the HSV-1 regulatory protein, ICP0, which antagonizes PML-I function. However, inhibiting phosphorylation at sites near the SUMO-interaction motif (SIM) of PML-I impairs its ability to respond to HSV-1 infection. Overall, our data suggest that PML phosphorylation regulates its antiviral activity against HSV-1. Full article

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2778 KiB

Open AccessArticle

Triple Cytokine FluoroSpot Analysis of Human Antigen-Specific IFN-γ, IL-17A and IL-22 Responses

by Tomas Dillenbeck, Eva Gelius, Jenny Fohlstedt and Niklas Ahlborg

Cells 2014, 3(4), 1116-1130; https://doi.org/10.3390/cells3041116 - 27 Nov 2014

Cited by 13 | Viewed by 7429

Abstract

The involvement of T-helper (Th)1, Th17 and Th22 cell subsets, in immunity, as well as in pathological inflammatory reactions, makes it important to determine their relative proportion. A triple FluoroSpot detecting the hallmark cytokines of Th1 (IFN-γ), Th17 (IL-17A) and Th22 (IL-22) was [...] Read more.

The involvement of T-helper (Th)1, Th17 and Th22 cell subsets, in immunity, as well as in pathological inflammatory reactions, makes it important to determine their relative proportion. A triple FluoroSpot detecting the hallmark cytokines of Th1 (IFN-γ), Th17 (IL-17A) and Th22 (IL-22) was developed and evaluated using human peripheral blood mononuclear cells from healthy donors incubated with tetanus toxoid, Candida albicans extract, mycobacterial purified protein derivative or medium only. Antigen stimulation yielded mainly cells secreting IFN-γ, IL-17A or IL-22 alone but lower proportions of double-secreting cells were also found; triple-secreting cells were rare. The response to C. albicans contrasted in that higher proportions of IL-17A single secreting as well as co-secreting cells, in particular IL-17A/IL-22, were found. The FluoroSpot analysis correlated well with single cytokine ELISpot assays ran in parallel and the methods displayed a comparable sensitivity. The results demonstrate the functionality of the FluoroSpot assay for simultaneous analysis of distinct Th1, Th17, Th22 as well as intermediate cell populations. The method provides a mean for a simple and rapid analysis of the involvement of these cells in immunity and disease. Full article

(This article belongs to the Special Issue ELISPOT Research)

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3695 KiB

Open AccessArticle

Stepping up ELISpot: Multi-Level Analysis in FluoroSpot Assays

by Sylvia Janetzki, Markus Rueger and Tomas Dillenbeck

Cells 2014, 3(4), 1102-1115; https://doi.org/10.3390/cells3041102 - 27 Nov 2014

Cited by 32 | Viewed by 11385

Abstract

ELISpot is one of the most commonly used immune monitoring assays, which allows the functional assessment of the immune system at the single cell level. With its outstanding sensitivity and ease of performance, the assay has recently advanced from the mere single function [...] Read more.

ELISpot is one of the most commonly used immune monitoring assays, which allows the functional assessment of the immune system at the single cell level. With its outstanding sensitivity and ease of performance, the assay has recently advanced from the mere single function cell analysis to multifunctional analysis by implementing detection reagents that are labeled with fluorophores (FluoroSpot), allowing the detection of secretion patterns of two or more analytes in a single well. However, the automated evaluation of such assays presents various challenges for image analysis. Here we dissect the technical and methodological requirements for a reliable analysis of FluoroSpot assays, introduce important quality control measures and provide advice for proper interpretation of results obtained by automated imaging systems. Full article

(This article belongs to the Special Issue ELISPOT Research)

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932 KiB

Open AccessReview

Natural and Synthetic Modulators of the TRPM7 Channel

by Vladimir Chubanov, Sebastian Schäfer, Silvia Ferioli and Thomas Gudermann

Cells 2014, 3(4), 1089-1101; https://doi.org/10.3390/cells3041089 - 27 Nov 2014

Cited by 46 | Viewed by 8979

Abstract

Transient receptor potential cation channel subfamily M member 7 (TRPM7) is a bi-functional protein comprising a TRP ion channel segment linked to an α-type protein kinase domain. Genetic inactivation of TRPM7 revealed its central role in magnesium metabolism, cell motility, proliferation and differentiation. [...] Read more.

Transient receptor potential cation channel subfamily M member 7 (TRPM7) is a bi-functional protein comprising a TRP ion channel segment linked to an α-type protein kinase domain. Genetic inactivation of TRPM7 revealed its central role in magnesium metabolism, cell motility, proliferation and differentiation. TRPM7 is associated with anoxic neuronal death, cardiac fibrosis and tumor progression highlighting TRPM7 as a new drug target. Recently, several laboratories have independently identified pharmacological compounds inhibiting or activating the TRPM7 channel. The recently found TRPM7 modulators were used as new experimental tools to unravel cellular functions of the TRPM7 channel. Here, we provide a concise overview of this emerging field. Full article

(This article belongs to the Special Issue Transient Receptor Potential (TRP) Channels)

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8072 KiB

Open AccessReview

Versatile Roles of K63-Linked Ubiquitin Chains in Trafficking

by Zoi Erpapazoglou, Olivier Walker and Rosine Haguenauer-Tsapis

Cells 2014, 3(4), 1027-1088; https://doi.org/10.3390/cells3041027 - 12 Nov 2014

Cited by 137 | Viewed by 14181

Abstract

Modification by Lys63-linked ubiquitin (UbK63) chains is the second most abundant form of ubiquitylation. In addition to their role in DNA repair or kinase activation, UbK63 chains interfere with multiple steps of intracellular trafficking. UbK63 chains decorate many plasma membrane proteins, providing a [...] Read more.

Modification by Lys63-linked ubiquitin (UbK63) chains is the second most abundant form of ubiquitylation. In addition to their role in DNA repair or kinase activation, UbK63 chains interfere with multiple steps of intracellular trafficking. UbK63 chains decorate many plasma membrane proteins, providing a signal that is often, but not always, required for their internalization. In yeast, plants, worms and mammals, this same modification appears to be critical for efficient sorting to multivesicular bodies and subsequent lysosomal degradation. UbK63 chains are also one of the modifications involved in various forms of autophagy (mitophagy, xenophagy, or aggrephagy). Here, in the context of trafficking, we report recent structural studies investigating UbK63 chains assembly by various E2/E3 pairs, disassembly by deubiquitylases, and specifically recognition as sorting signals by receptors carrying Ub-binding domains, often acting in tandem. In addition, we address emerging and unanticipated roles of UbK63 chains in various recycling pathways that function by activating nucleators required for actin polymerization, as well as in the transient recruitment of signaling molecules at the plasma or ER membrane. In this review, we describe recent advances that converge to elucidate the mechanisms underlying the wealth of trafficking functions of UbK63 chains. Full article

(This article belongs to the Special Issue Protein Ubiquitination)

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Open AccessReview

Regulation of Cardiac Cell Fate by microRNAs: Implications for Heart Regeneration

by Margarida Gama-Carvalho, Jorge Andrade and Luis Brás-Rosário

Cells 2014, 3(4), 996-1026; https://doi.org/10.3390/cells3040996 - 29 Oct 2014

Cited by 29 | Viewed by 12930

Abstract

microRNAs are post-transcriptional regulators of gene expression that have been shown to be central players in the establishment of cellular programs, often acting as switches that control the choice between proliferation and differentiation during development and in adult tissues. The heart develops from [...] Read more.

microRNAs are post-transcriptional regulators of gene expression that have been shown to be central players in the establishment of cellular programs, often acting as switches that control the choice between proliferation and differentiation during development and in adult tissues. The heart develops from two small patches of cells in the mesoderm, the heart fields, which originate the different cardiac cell types, including cardiomyocytes, vascular smooth muscle and endothelial cells. These progenitors proliferate and differentiate to establish a highly connected three-dimensional structure, involving a robust succession of gene expression programs strongly influenced by microRNAs. Although the mammalian heart has conventionally been viewed as a post-mitotic organ, cardiac cells have recently been shown to display some regenerative potential, which is nonetheless insufficient to regenerate heart lesions, in contrast with other vertebrates like the zebrafish. Both the proliferation of adult cardiac stem cells and the ability of cardiomyocytes to re-enter the cell cycle have been proposed to sustain these regenerative processes. Here we review the role of microRNAs in the control of stem cell and cardiomyocyte dependent cardiac regeneration processes, and discuss potential applications for the treatment of cardiac injury. Full article

(This article belongs to the Special Issue MicroRNAs in Cardiovascular Biology and Disease)

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594 KiB

Open AccessCorrection

Correction: Sadofsky, L.R., et al. Unique Responses are Observed in Transient Receptor Potential Ankyrin 1 and Vanilloid 1 (TRPA1 and TRPV1) Co-Expressing Cells. Cells 2014, 3, 616-626

by Laura R. Sadofsky, Koti T. Sreekrishna, Yakang Lin, Renee Schinaman, Kate Gorka, Yogita Mantri, John Christian Haught, Thomas G. Huggins, Robert J. Isfort, Charles C. Bascom and Alyn H. Morice

Cells 2014, 3(4), 994-995; https://doi.org/10.3390/cells3040994 - 27 Oct 2014

Viewed by 4634

Abstract

The authors wish to make the following corrections to this paper [1]: In Table 2 on page 623, the Quercinitol activation value for TRPA1V1 should be 2.3 instead of 57.6. Quercinitol does not activate TRPA1V1. We thank Michael J.M. Fisher (University of Erlangen, [...] Read more.

The authors wish to make the following corrections to this paper [1]: In Table 2 on page 623, the Quercinitol activation value for TRPA1V1 should be 2.3 instead of 57.6. Quercinitol does not activate TRPA1V1. We thank Michael J.M. Fisher (University of Erlangen, Germany) for his feedback which helped us to review our result. The authors would like to apologize for any inconvenience caused to the readers by these changes. Full article

(This article belongs to the Special Issue Transient Receptor Potential (TRP) Channels)

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Open AccessReview

Regulation of TGF-β Superfamily Signaling by SMAD Mono-Ubiquitination

by Feng Xie, Zhengkui Zhang, Hans Van Dam, Long Zhang and Fangfang Zhou

Cells 2014, 3(4), 981-993; https://doi.org/10.3390/cells3040981 - 15 Oct 2014

Cited by 59 | Viewed by 13464

Abstract

TGF-β(transforming growth factor-β) superfamily signaling mediators are important regulators of diverse physiological and pathological events. TGF-β signals are transduced by transmembrane type I and type II serine/threonine kinase receptors and their downstream effectors, the SMAD(drosophila mothers against decapentaplegic protein) proteins. Numerous studies have [...] Read more.

TGF-β(transforming growth factor-β) superfamily signaling mediators are important regulators of diverse physiological and pathological events. TGF-β signals are transduced by transmembrane type I and type II serine/threonine kinase receptors and their downstream effectors, the SMAD(drosophila mothers against decapentaplegic protein) proteins. Numerous studies have already demonstrated crucial regulatory roles for modification of TGF-β pathway components by poly-ubiquitination. Recently, several studies also uncovered mono-ubiquitination of SMADs as a mechanism for SMAD activation or inactivation. Mono-ubiquitination and subsequent deubiquitination of SMAD proteins accordingly play important roles in the control of TGF-β superfamily signaling. This review highlights the major pathways regulated by SMAD mono-ubiquitination. Full article

(This article belongs to the Special Issue Protein Ubiquitination)

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Open AccessReview

MicroRNAs Regulate Vascular Medial Calcification

by Jane A. Leopold

Cells 2014, 3(4), 963-980; https://doi.org/10.3390/cells3040963 - 14 Oct 2014

Cited by 57 | Viewed by 9472

Abstract

Vascular calcification is highly prevalent in patients with coronary artery disease and, when present, is associated with major adverse cardiovascular events, including an increased risk of cardiovascular mortality. The pathogenesis of vascular calcification is complex and is now recognized to recapitulate skeletal bone [...] Read more.

Vascular calcification is highly prevalent in patients with coronary artery disease and, when present, is associated with major adverse cardiovascular events, including an increased risk of cardiovascular mortality. The pathogenesis of vascular calcification is complex and is now recognized to recapitulate skeletal bone formation. Vascular smooth muscle cells (SMC) play an integral role in this process by undergoing transdifferentiation to osteoblast-like cells, elaborating calcifying matrix vesicles and secreting factors that diminish the activity of osteoclast-like cells with mineral resorbing capacity. Recent advances have identified microRNAs (miRs) as key regulators of this process by directing the complex genetic reprogramming of SMCs and the functional responses of other relevant cell types relevant for vascular calcification. This review will detail SMC and bone biology as it relates to vascular calcification and relate what is known to date regarding the regulatory role of miRs in SMC-mediated vascular calcification. Full article

(This article belongs to the Special Issue MicroRNAs in Cardiovascular Biology and Disease)

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1788 KiB

Open AccessReview

Classical Transient Receptor Potential 1 (TRPC1): Channel or Channel Regulator?

by Alexander Dietrich, Meike Fahlbusch and Thomas Gudermann

Cells 2014, 3(4), 939-962; https://doi.org/10.3390/cells3040939 - 29 Sep 2014

Cited by 67 | Viewed by 10426

Abstract

In contrast to other Classical Transient Receptor Potential TRPC channels the function of TRPC1 as an ion channel is a matter of debate, because it is often difficult to obtain substantial functional signals over background in response to over-expression of TRPC1 alone. Along [...] Read more.

In contrast to other Classical Transient Receptor Potential TRPC channels the function of TRPC1 as an ion channel is a matter of debate, because it is often difficult to obtain substantial functional signals over background in response to over-expression of TRPC1 alone. Along these lines, heterologously expressed TRPC1 is poorly translocated to the plasma membrane as a homotetramer and may not function on its own physiologically, but may rather be an important linker and regulator protein in heteromeric TRPC channel tetramers. However, due to the lack of specific TRPC1 antibodies able to detect native TRPC1 channels in primary cells, identification of functional TRPC1 containing heteromeric TRPC channel complexes in the plasma membrane is still challenging. Moreover, an extended TRPC1 cDNA, which was recently discovered, may seriously question results obtained in heterologous expression systems transfected with shortened cDNA versions. Therefore, this review will focus on the current status of research on TRPC1 function obtained in primary cells and a TRPC1-deficient mouse model. Full article

(This article belongs to the Special Issue Transient Receptor Potential (TRP) Channels)

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Cells, Volume 3, Issue 4 (December 2014) – 10 articles , Pages 939-1158

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