scholarly journals Spatial Turing-type Pattern Formation in a Model of Signal Transduction Involving Membrane-based Receptors Coupled by G Proteins

2006 ◽  
Vol 2 ◽  
pp. 117693510600200
Author(s):  
Chontita Rattanakul ◽  
Yongwimon Lenbury ◽  
Jonathan Bell ◽  
Varanuj Chatsudthipong ◽  
Wannapong Triampo ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Cell Membrane ◽  
G Proteins ◽  
Surface Membrane ◽  
Reaction Diffusion ◽  
Nonlinear Stability Analysis ◽  
Functional Responses ◽  
Weakly Nonlinear ◽  
Messenger Molecules ◽  
Type Pattern

In this paper, a model of signaling pathways involving G proteins is investigated. The model incorporates reaction-diffusion mechanisms in which various reactants participate inside and on the extra-cellular surface membrane. The messenger molecules may diffuse over the surface of the cell membrane and signal transduction across the cell membrane is mediated by membrane receptor bound proteins which connect the genetically controlled biochemical intra-cellular reactions to the production of the second messenger, leading to desired functional responses. Dynamic and steady-state properties of the model are then investigated through weakly nonlinear stability analysis. Turing-type patterns are shown to form robustly under different delineating conditions on the system parameters. The theoretical predictions are then discussed in the context of some recently reported experimental evidence.

scholarly journals Every Detail Matters. That Is, How the Interaction between Gα Proteins and Membrane Affects Their Function

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 222
Author(s):  
Agnieszka Polit ◽  
Paweł Mystek ◽  
Ewa Błasiak
Keyword(s):  
Signal Transduction ◽  
G Protein ◽  
G Proteins ◽  
Lipid Membranes ◽  
Signaling Proteins ◽  
Heterotrimeric G Proteins ◽  
Membrane Attachment ◽  
The Individual ◽  
Multicellular Organisms ◽  
G Protein Coupled

In highly organized multicellular organisms such as humans, the functions of an individual cell are dependent on signal transduction through G protein-coupled receptors (GPCRs) and subsequently heterotrimeric G proteins. As most of the elements belonging to the signal transduction system are bound to lipid membranes, researchers are showing increasing interest in studying the accompanying protein–lipid interactions, which have been demonstrated to not only provide the environment but also regulate proper and efficient signal transduction. The mode of interaction between the cell membrane and G proteins is well known. Despite this, the recognition mechanisms at the molecular level and how the individual G protein-membrane attachment signals are interrelated in the process of the complex control of membrane targeting of G proteins remain unelucidated. This review focuses on the mechanisms by which mammalian Gα subunits of G proteins interact with lipids and the factors responsible for the specificity of membrane association. We summarize recent data on how these signaling proteins are precisely targeted to a specific site in the membrane region by introducing well-defined modifications as well as through the presence of polybasic regions within these proteins and interactions with other components of the heterocomplex.

scholarly journals Dual coupling of the α-thrombin receptor to signal-transduction pathways involving phosphatidylinositol and phosphatidylcholine metabolism

1998 ◽  
Vol 337 (1) ◽  
pp. 97-104 ◽  
Author(s):  
Jie CHENG ◽  
Joseph J. BALDASSARE ◽  
Daniel M. RABEN
Keyword(s):  
Signal Transduction ◽  
Cleavage Site ◽  
Thrombin Receptor ◽  
Signal Transduction Pathways ◽  
Metabolizing Enzymes ◽  
Thrombin Cleavage ◽  
Messenger Molecules ◽  
Mitogenic Signalling ◽  
Signalling Cascade ◽  
Phosphatidylcholine Metabolism

Addition of α-thrombin to quiescent IIC9 cells results in the activation of lipid-metabolizing enzymes associated with signal-transduction cascades. These enzymes include phosphatidylinositol (PI)-specific phospholipase C (PI-PLC), phosphatidylcholine (PC)-specific phospholipases C and D and phospholipase A2 (PLA2). Whereas the α-thrombin receptor has been shown to couple with PI-PLCs, it is not clear whether this receptor, or a putative second receptor, couples to one or more of the other phospholipases. In this report we determine whether the cloned receptor couples to all or a subset of these enzymes. We show that (i) an α-thrombin-receptor-activating peptide also elicits the above responses and (ii) addition of enterokinase to IIC9 cells, stably transfected with an α-thrombin receptor (enterokinase- responsive α-thrombin receptor, EKTR) containing an enterokinase cleavage site in place of an α-thrombin cleavage site, stimulates both PI and PC hydrolysis, including PLA2. Enterokinase also induces mitogenesis in the IIC9s transfected with EKTR. These results indicate that, in addition to initiating a mitogenic signalling cascade, the cloned α-thrombin receptor couples to enzymes involved in generating PC-derived, as well as PI-derived, second-messenger molecules in IIC9s. Additionally, using the cells transfected with EKTR, we further demonstrate that only activated, i.e. cleaved, receptors are desensitized.

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