Differential localization and anabolic responsiveness of mTOR complexes in human skeletal muscle in response to feeding and exercise
Mechanistic target of rapamycin (mTOR) resides as two complexes within skeletal muscle. mTOR complex 1 [mTORC1–regulatory associated protein of mTOR (Raptor) positive] regulates skeletal muscle growth, whereas mTORC2 [rapamycin-insensitive companion of mTOR (Rictor) positive] regulates insulin sensitivity. To examine the regulation of these complexes in human skeletal muscle, we utilized immunohistochemical analysis to study the localization of mTOR complexes before and following protein-carbohydrate feeding (FED) and resistance exercise plus protein-carbohydrate feeding (EXFED) in a unilateral exercise model. In bas...
Source: AJP: Cell Physiology - December 1, 2017 Category: Cytology Authors: Hodson, N., McGlory, C., Oikawa, S. Y., Jeromson, S., Song, Z., Rüegg, M. A., Hamilton, D. L., Phillips, S. M., Philp, A. Tags: RAPID REPORT Source Type: research

Possible roles for ATP release from RBCs exclude the cAMP-mediated Panx1 pathway
Red blood cell (RBC)-derived adenosine triphosphate (ATP) has been proposed as an integral component in the regulation of oxygen supply to skeletal muscle. In ex vivo settings RBCs have been shown to release ATP in response to a number of stimuli, including stimulation of adrenergic receptors. Further evidence suggested that ATP release from RBCs was dependent on activation of adenylate cyclase (AC)/cyclic adenosine monophosphate (cAMP)-dependent pathways and involved the pannexin 1 (Panx1) channel. Here we show that RBCs express Panx1 and confirm its absence in Panx1 knockout (–/–) RBCs. However, Panx1–/...
Source: AJP: Cell Physiology - December 1, 2017 Category: Cytology Authors: Keller, A. S., Diederich, L., Panknin, C., DeLalio, L. J., Drake, J. C., Sherman, R., Jackson, E. K., Yan, Z., Kelm, M., Cortese-Krott, M. M., Isakson, B. E. Tags: RESEARCH ARTICLE Source Type: research

RING finger protein 113A regulates C-X-C chemokine receptor type 4 stability and signaling
As an α-chemokine receptor specific for stromal-derived-factor-1 (SDF-1, also called CXCL12), C-X-C chemokine receptor type 4 (CXCR4) plays a vital role in chemotactically attracting lymphocytes during inflammation. CXCR4 also regulates HIV infection due to its role as one of the chemokine coreceptors for HIV entry into CD4+ T cells. Chemokine receptors and their signaling pathways have been shown to be regulated by the process of ubiquitination, a posttranslational modification, guided by ubiquitin E3 ligases, which covalently links ubiquitin chains to lysine residues within target substrates. Here we describe a nov...
Source: AJP: Cell Physiology - November 7, 2017 Category: Cytology Authors: Lear, T., Dunn, S. R., McKelvey, A. C., Mir, A., Evankovich, J., Chen, B. B., Liu, Y. Tags: RESEARCH ARTICLE Source Type: research

In vitro contraction protects against palmitate-induced insulin resistance in C2C12 myotubes
We are interested in understanding mechanisms that govern the protective role of exercise against lipid-induced insulin resistance, a key driver of type 2 diabetes. In this context, cell culture models provide a level of abstraction that aid in our understanding of cellular physiology. Here we describe the development of an in vitro myotube contraction system that provides this protective effect, and which we have harnessed to investigate lipid-induced insulin resistance. C2C12 myocytes were differentiated into contractile myotubes. A custom manufactured platinum electrode system and pulse stimulator, with polarity switchi...
Source: AJP: Cell Physiology - November 7, 2017 Category: Cytology Authors: Nieuwoudt, S., Mulya, A., Fealy, C. E., Martelli, E., Dasarathy, S., Naga Prasad, S. V., Kirwan, J. P. Tags: RESEARCH ARTICLE Source Type: research

Oxidized low-density lipoprotein-induced microparticles promote endothelial monocyte adhesion via intercellular adhesion molecule 1
In this study, we aim to determine the influence of oxLDL on endothelial microparticle release and the subsequent regulation of the endothelial activation. EMPs were collected from the medium of human umbilical vein endothelial cells (HUVECs) treated with oxLDL or PBS as control. We find that oxLDL increases the release of EMPs containing intercellular adhesion molecule 1 (ICAM-1) but not vascular cell adhesion molecule 1 (VCAM-1). Confocal microscopy analysis further demonstrates that these EMPs interact with endothelial cells and increase the expression of ICAM-1 in HUVECs. The fact that injecting oxLDL-induced EMPs via ...
Source: AJP: Cell Physiology - November 7, 2017 Category: Cytology Authors: Fu, Z., Zhou, E., Wang, X., Tian, M., Kong, J., Li, J., Ji, L., Niu, C., Shen, H., Dong, S., Liu, C., Vermorken, A., Willard, B., Zu, L., Zheng, L. Tags: RESEARCH ARTICLE Source Type: research

Detachment-induced E-cadherin expression promotes 3D tumor spheroid formation but inhibits tumor formation and metastasis of lung cancer cells
The epithelial-to-mesenchymal transition is proposed to be a key mechanism responsible for metastasis-related deaths. Similarly, cancer stem cells (CSCs) have been proposed to be a key driver of tumor metastasis. However, the link between the two events and their control mechanisms is unclear. We used a three-dimensional (3D) tumor spheroid assay and other CSC-indicating assays to investigate the role of E-cadherin in CSC regulation and its association to epithelial-to-mesenchymal transition in lung cancer cells. Ectopic overexpression and knockdown of E-cadherin were found to promote and retard, respectively, the formatio...
Source: AJP: Cell Physiology - November 7, 2017 Category: Cytology Authors: Powan, P., Luanpitpong, S., He, X., Rojanasakul, Y., Chanvorachote, P. Tags: RESEARCH ARTICLE Source Type: research

Integration of TRPC6 and NADPH oxidase activation in lysophosphatidylcholine-induced TRPC5 externalization
Lipid oxidation products, including lysophosphatidylcholine (lysoPC), activate canonical transient receptor potential 6 (TRPC6) channels, and the subsequent increase in intracellular Ca2+ leads to TRPC5 activation. The goal of this study is to elucidate the steps in the pathway between TRPC6 activation and TRPC5 externalization. Following TRPC6 activation by lysoPC, extracellular regulated kinase (ERK) is phosphorylated. This leads to phosphorylation of p47phox and subsequent NADPH oxidase activation with increased production of reactive oxygen species. ERK activation requires TRPC6 opening and influx of Ca2+ as evidenced ...
Source: AJP: Cell Physiology - November 7, 2017 Category: Cytology Authors: Chaudhuri, P., Rosenbaum, M. A., Birnbaumer, L., Graham, L. M. Tags: RESEARCH ARTICLE Source Type: research

Muscle paralysis induces bone marrow inflammation and predisposition to formation of giant osteoclasts
Transient muscle paralysis engendered by a single injection of botulinum toxin A (BTxA) rapidly induces profound focal bone resorption within the medullary cavity of adjacent bones. While initially conceived as a model of mechanical disuse, osteoclastic resorption in this model is disproportionately severe compared with the modest gait defect that is created. Preliminary studies of bone marrow following muscle paralysis suggested acute upregulation of inflammatory cytokines, including TNF-α and IL-1. We therefore hypothesized that BTxA-induced muscle paralysis would rapidly alter the inflammatory microenvironment and...
Source: AJP: Cell Physiology - November 7, 2017 Category: Cytology Authors: Ausk, B. J., Worton, L. E., Smigiel, K. S., Kwon, R. Y., Bain, S. D., Srinivasan, S., Gardiner, E. M., Gross, T. S. Tags: RESEARCH ARTICLE Source Type: research

Molecular insights into the normal operation, regulation, and multisystemic roles of K+-Cl- cotransporter 3 (KCC3)
Long before the molecular identity of the Na+-dependent K+-Cl– cotransporters was uncovered in the mid-nineties, a Na+-independent K+-Cl– cotransport system was also known to exist. It was initially observed in sheep and goat red blood cells where it was shown to be ouabain-insensitive and to increase in the presence of N-ethylmaleimide (NEM). After it was established between the early and mid-nineties, the expressed sequence tag (EST) databank was found to include a sequence that was highly homologous to those of the Na+-dependent K+-Cl– cotransporters. This sequence was eventually found to code for the ...
Source: AJP: Cell Physiology - November 7, 2017 Category: Cytology Authors: Garneau, A. P., Marcoux, A. A., Frenette-Cotton, R., Mac-Way, F., Lavoie, J. L., Isenring, P. Tags: REVIEW Source Type: research

PLK1 regulates spindle association of phosphorylated eukaryotic translation initiation factor 4E-binding protein and spindle function in mouse oocytes
Oocyte meiotic spindles are associated with spindle-enriched mRNAs, phosphorylated ribosome protein S6, and phosphorylated variants of the key translational regulator, eukaryotic translation initiation factor 4E-binding protein 1 (eIF4E-BP1), consistent with translational control of localized mRNAs by eIF4E-BP1 in facilitating spindle formation and stability. Using specific kinase inhibitors, we determined which kinases regulate phosphorylation status of eIF4E-BP1 associated with meiotic spindles in mouse oocytes and effects of kinase inhibition on chromosome congression and spindle formation. Neither ataxia telangiectasia...
Source: AJP: Cell Physiology - November 1, 2017 Category: Cytology Authors: Severance, A. L., Latham, K. E. Tags: RESEARCH ARTICLE Source Type: research

Acute myotube protein synthesis regulation by IL-6-related cytokines
IL-6 and leukemia inhibitory factor (LIF), members of the IL-6 family of cytokines, play recognized paradoxical roles in skeletal muscle mass regulation, being associated with both growth and atrophy. Overload or muscle contractions can induce a transient increase in muscle IL-6 and LIF expression, which has a regulatory role in muscle hypertrophy. However, the cellular mechanisms involved in this regulation have not been completely identified. The induction of mammalian target of rapamycin complex 1 (mTORC1)-dependent myofiber protein synthesis is an established regulator of muscle hypertrophy, but the involvement of the ...
Source: AJP: Cell Physiology - November 1, 2017 Category: Cytology Authors: Gao, S., Durstine, J. L., Koh, H.-J., Carver, W. E., Frizzell, N., Carson, J. A. Tags: RESEARCH ARTICLE Source Type: research

The role of Ca2+-activated Cl- current in tone generation in the rabbit corpus cavernosum
In conclusion, although both drugs were effective blockers of IClCa, the effect of T16Ainh-A01 on L-type Ca2+ current precludes its use for evaluating the role of IClCa in tone generation. However, 10 μM CaCCinh-A01 selectively blocked IClCa versus L-type Ca2+ current and reduced spontaneous and PE-induced tone, suggesting that IClCa is important in maintaining penile detumescence. (Source: AJP: Cell Physiology)
Source: AJP: Cell Physiology - November 1, 2017 Category: Cytology Authors: Hannigan, K. I., Griffin, C. S., Large, R. J., Sergeant, G. P., Hollywood, M. A., McHale, N. G., Thornbury, K. D. Tags: RESEARCH ARTICLE Source Type: research

Corrigendum
(Source: AJP: Cell Physiology)
Source: AJP: Cell Physiology - October 9, 2017 Category: Cytology Tags: CORRIGENDUM Source Type: research

Reply to "Letter to the editor: Comments on Wette et al. (2017): 'Characterization of muscle ankyrin repeat proteins in human skeletal muscle"
(Source: AJP: Cell Physiology)
Source: AJP: Cell Physiology - October 9, 2017 Category: Cytology Authors: Wette, S. G., Smith, H. K., Lamb, G. D., Murphy, R. M. Tags: LETTER TO THE EDITOR Source Type: research

Letter to the editor: Comments on Wette et al. (2017): "Characterization of muscle ankyrin repeat proteins in human skeletal muscle"
(Source: AJP: Cell Physiology)
Source: AJP: Cell Physiology - October 9, 2017 Category: Cytology Authors: Cenni, V. Tags: LETTER TO THE EDITOR Source Type: research