scholarly journals Plasma membrane poration by opioid neuropeptides: a possible mechanism of pathological signal transduction

2015 ◽  
Vol 6 (3) ◽  
pp. e1683-e1683 ◽  
Author(s):  
O Maximyuk ◽  
V Khmyz ◽  
C-J Lindskog ◽  
V Vukojević ◽  
T Ivanova ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Plasma Membrane ◽  
Opioid Neuropeptides ◽  
Membrane Poration

scholarly journals Morphological Alterations of CAD Cells Overexpressing AKT1

2020 ◽  
Vol 26 (S2) ◽  
pp. 1354-1358
Author(s):  
James Wachira
Keyword(s):  
Signal Transduction ◽  
Plasma Membrane ◽  
Cell Survival ◽  
Fluorescent Protein ◽  
Morphological Changes ◽  
Protein Localization ◽  
Signal Transduction Pathways ◽  
Morphological Alterations ◽  
Cellular Models ◽  
Cad Cells

AbstractCAD cells are neuronal cells used in studies of cell differentiation and in cellular models of neuropathology. When cultured in differentiation medium, CAD cells exhibit characteristics of mature neurons including the generation of action potential. In addition to being a central signaling kinase in cell survival, AKT1 plays important roles in the nervous system including neuroplasticity and this study examined the localization of exogenous AKT1 in CAD cells. Neuropeptides modulate many signal transduction pathways and melacortins are implicated in regulating growth factor signal transduction pathways, including the PI3K/AKT pathway. AKT1-DsReD was transfected into CAD cells that were stably expressing melanocortin 3-receptor-GFP (MC3R-GFP), a G-protein coupled receptor. The cells were imaged with confocal microscopy to determine the fluorescent protein localization patterns. AKT1-DsRed was predominantly localized in the cytoplasm and the nucleus. Further, expression of exogenous AKT1 in these cell lines led to morphological changes reminiscent of apoptosis. As expected, MC3R-GFP localized to the plasma membrane but it internalized upon cell stimulation with the cognate ligand. In limited areas of the plasma membrane, AKT1-DsRed and MC3R-GFP were colocalized. In conclusion, quantitative studies to understand the role of relative levels of AKT1 in determining cell survival are needed.

scholarly journals Fluorescent, short-chain C6-NBD-sphingomyelin, but not C6-NBD-glucosylceramide, is subject to extensive degradation in the plasma membrane: implications for signal transduction related to cell differentiation

1995 ◽  
Vol 309 (3) ◽  
pp. 905-912 ◽  
Author(s):  
J W Kok ◽  
T Babia ◽  
K Klappe ◽  
D Hoekstra
Keyword(s):  
Signal Transduction ◽  
Plasma Membrane ◽  
Cell Differentiation ◽  
Plasma Membranes ◽  
Cell Types ◽  
Short Chain ◽  
Synthetic Activity ◽  
Intact Cells ◽  
Ht29 Cells ◽  
Extensive Degradation

The involvement of the plasma membrane in the metabolism of the sphingolipids sphingomyelin (SM) and glucosylceramide (GlcCer) was studied, employing fluorescent short-chain analogues of these lipids, 6-[N-(7-nitro-2,1,3-benzoxadiazol-4-yl) amino]hexanoylsphingosylphosphorylcholine (C6-NBD-SM), C6-NBD-GlcCer and their common biosynthetic precursor C6-NBD-ceramide (C6-NBD-Cer). Although these fluorescent short-chain analogues are metabolically active, some caution is to be taken in view of potential changes in biophysical/biochemical properties of the lipid compared with its natural counterpart. However, these short-chain analogues offer the advantage of studying the lipid metabolic enzymes in their natural environment, since detergent solubilization is not necessary for measuring their activity. These studies were carried out with several cell types, including two phenotypes (differing in state of differentiation) of HT29 cells. Degradation and biosynthesis of C6-NBD-SM and C6-NBD-GlcCer were determined in intact cells, in their isolated plasma membranes, and in plasma membranes isolated from rat liver tissue. C6-NBD-SM was found to be subject to extensive degradation in the plasma membrane, due to neutral sphingomyelinase (N-SMase) activity. The extent of C6-NBD-SM hydrolysis showed a general cell-type dependence and turned out to be dependent on the state of cell differentiation, as revealed for HT29 cells. In undifferentiated HT29 cells N-SMase activity was at least threefold higher than in its differentiated counterpart. In contrast, in all cell types studied, very little if any biosynthesis of C6-NBD-SM from the precursor C6-NBD-Cer occurred. Moreover, in the case of C6-NBD-GlcCer, neither hydrolytic nor synthetic activity was found to be associated with the plasma membrane. These results are discussed in the context of the involvement of the sphingolipids SM and GlcCer in signal transduction pathways in the plasma membrane.

Kinase-anchoring proteins in ciliary signal transduction

2021 ◽  
Vol 478 (8) ◽  
pp. 1617-1629
Author(s):  
Janani Gopalan ◽  
Linda Wordeman ◽  
John D. Scott
Keyword(s):  
Signal Transduction ◽  
Brownian Motion ◽  
Plasma Membrane ◽  
Primary Cilium ◽  
Regulatory Proteins ◽  
Macromolecular Complexes ◽  
Regulatory Enzymes ◽  
Ciliary Function ◽  
Anchoring Proteins ◽  
Signal Relay

Historically, the diffusion of chemical signals through the cell was thought to occur within a cytoplasmic soup bounded by the plasma membrane. This theory was predicated on the notion that all regulatory enzymes are soluble and moved with a Brownian motion. Although enzyme compartmentalization was initially rebuffed by biochemists as a ‘last refuge of a scoundrel', signal relay through macromolecular complexes is now accepted as a fundamental tenet of the burgeoning field of spatial biology. A-Kinase anchoring proteins (AKAPs) are prototypic enzyme-organizing elements that position clusters of regulatory proteins at defined subcellular locations. In parallel, the primary cilium has gained recognition as a subcellular mechanosensory organelle that amplifies second messenger signals pertaining to metazoan development. This article highlights advances in our understanding of AKAP signaling within the primary cilium and how defective ciliary function contributes to an increasing number of diseases known as ciliopathies.

Mechanisms of Hormone Action

2011 ◽  
Author(s):  
Stephen R. Hammes ◽  
Carole R. Mendelson
Keyword(s):  
Signal Transduction ◽  
Plasma Membrane ◽  
Nuclear Receptors ◽  
Plasma Membranes ◽  
Hormone Receptors ◽  
Membrane Receptors ◽  
Endocrine Disorders ◽  
Messenger Rnas ◽  
Dihydroxyvitamin D3 ◽  
Transduction Mechanisms

The capacity of a cell to respond to a particular hormone depends on the presence of cellular receptors specific for that hormone. After binding hormone, the receptor is biochemically and structurally altered, resulting in its activation; the activated receptor then mediates all of the actions of the hormone on the cell. The steroid and thyroid hormones as well as retinoids and 1,25-dihydroxyvitamin D3 diffuse freely through the lipophilic plasma membrane of the cell and interact with receptors that are primarily within the nucleus. On activation, the receptors alter the transcription of specific genes, resulting in changes in the levels of specific messenger RNAs (mRNAs), which are in turn translated into proteins. Hormones that are water soluble, such as the peptide and polypeptide hormones, catecholamines, and other neurotransmitters, as well as the relatively hydrophobic prostaglandins, interact with receptors in the plasma membrane. After hormone binding, the activated membrane receptors initiate signal transduction cascades that result in changes in enzyme activities and alterations in gene expression. In this chapter, the properties of various classes of receptors that are localized within the plasma membranes of target cells and the signal transduction mechanisms that mediate interactions with their ligands will first be addressed. This will be followed by consideration of the structural properties of the nuclear hormone receptors, the events that result in their activation, and the mechanisms whereby the activated nuclear receptors alter the expression of specific genes. Finally, a number of endocrine disorders that are caused by alterations in the number and/or function of plasma membranes and nuclear receptors will be reviewed. The function of a receptor is to recognize a particular hormone among all the molecules in the environment of the cell at a given time and, after binding the hormone, to transmit a signal that ultimately results in a biological response. Hormones are normally present in the circulation in extremely low concentrations, ranging from 10 –9 to 10 –11 M.

Intracellular signalling

2010 ◽  
pp. 169-176
Author(s):  
R. Andres Floto
Keyword(s):  
Signal Transduction ◽  
Plasma Membrane ◽  
Cell Surface ◽  
Intracellular Signalling ◽  
Cell Surface Receptors ◽  
Surface Receptors ◽  
Transmission Of Information ◽  
Effective Transmission

This section outlines the general principles of intracellular signalling. Focusing on cell surface receptors, the requirements for effective transmission of information across the plasma membrane are outlined. The principal mechanisms utilized in mammalian signal transduction are described. For each, the pathological consequences of aberrant signalling and means by which pathways can be pharmacologically targeted are described in molecular terms....

Intracellular signalling

2020 ◽  
pp. 256-265
Author(s):  
R. Andres Floto
Keyword(s):  
Signal Transduction ◽  
Plasma Membrane ◽  
Cell Surface ◽  
Intracellular Signalling ◽  
Signalling Pathways ◽  
Molecular Processes ◽  
Surface Receptors ◽  
Intracellular Signalling Pathways ◽  
Transmission Of Information ◽  
Effective Transmission

This chapter outlines the general principles of intracellular signalling. Focusing on cell surface receptors, the requirements for effective transmission of information across the plasma membrane are outlined. The principal mechanisms utilized in mammalian signal transduction are described. For each, the pathological consequences of aberrant signalling and means by which pathways can be pharmacologically targeted are described in molecular terms. Intracellular signalling pathways permit the transmission and integration of information within cells. Mammalian receptor signalling relies on only a small number of distinct molecular processes which interact to determine cellular responses. Rapid advances in our knowledge of the mechanisms of intracellular signalling has greatly increased understanding of how cells function physiologically, how they malfunction pathologically, and how their behaviour might be manipulated therapeutically.

scholarly journals Signal Transduction across the Nuclear Envelope: Role of the LINC Complex in Bidirectional Signaling

Cells ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 124 ◽  
Author(s):  
Miki Hieda
Keyword(s):  
Signal Transduction ◽  
Plasma Membrane ◽  
Nuclear Envelope ◽  
Cell Cycle Progression ◽  
Structural Integrity ◽  
Short Review ◽  
Linc Complex ◽  
Cellular Functions ◽  
Bidirectional Signaling ◽  
Extracellular Signal

The primary functions of the nuclear envelope are to isolate the nucleoplasm and its contents from the cytoplasm as well as maintain the spatial and structural integrity of the nucleus. The nuclear envelope also plays a role in the transfer of various molecules and signals to and from the nucleus. To reach the nucleus, an extracellular signal must be transmitted across three biological membranes: the plasma membrane, as well as the inner and outer nuclear membranes. While signal transduction across the plasma membrane is well characterized, signal transduction across the nuclear envelope, which is essential for cellular functions such as transcriptional regulation and cell cycle progression, remains poorly understood. As a physical entity, the nuclear envelope, which contains more than 100 proteins, functions as a binding scaffold for both the cytoskeleton and the nucleoskeleton, and acts in mechanotransduction by relaying extracellular signals to the nucleus. Recent results show that the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex, which is a conserved molecular bridge that spans the nuclear envelope and connects the nucleoskeleton and cytoskeleton, is also capable of transmitting information bidirectionally between the nucleus and the cytoplasm. This short review discusses bidirectional signal transduction across the nuclear envelope, with a particular focus on mechanotransduction.

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