Logical identification of all steady states: The concept of feedback loop characteristic states

1993 ◽  
Vol 55 (5) ◽  
pp. 973-991 ◽  
Author(s):  
E SNOUSSI ◽  
R THOMAS
Keyword(s):  
Feedback Loop ◽  
Steady States

scholarly journals Stability analysis of a signaling circuit with dual species of GTPase switches

2020 ◽  
Author(s):  
Lucas Martins Stolerman ◽  
Pradipta Ghosh ◽  
Padmini Rangamani
Keyword(s):  
Stability Analysis ◽  
Feedback Loop ◽  
Network Motif ◽  
Bound State ◽  
Steady States ◽  
Eukaryotic Cells ◽  
Nucleotide Exchange ◽  
Organelle Biogenesis ◽  
Stable States ◽  
Wide Range

GTPases are molecular switches that regulate a wide range of cellular processes, such as organelle biogenesis, position, shape, and function, vesicular transport between organelles, and signal transduction. These hydrolase enzymes operate by toggling between an active "ON") guanosine triphosphate (GTP)-bound state and an inactive ("OFF") guanosine diphosphate (GDP)-bound state; such a toggle is regulated by GEFs (guanine nucleotide exchange factors) and GAPs (GTPase activating proteins). Here we propose a model for a network motif between monomeric (m) and trimeric (t) GTPases assembled exclusively in eukaryotic cells of multicellular organisms. We develop a system of ordinary differential equations in which these two classes of GTPases are interlinked conditional to their ON/OFF states within a motif through coupling and feedback loops. We provide explicit formulae for the steady states of the system and perform classical local stability analysis to systematically investigate the role of the different connections between the GTPase switches. Interestingly, a coupling of the active mGTPase to the GEF of the tGTPase was sufficient to provide two locally stable states: one where both active/inactive forms of the mGTPase can be interpreted as having low concentrations and the other where both m- and tGTPase have high concentrations. Moreover, when a feedback loop from the GEF of the tGTPase to the GAP of the mGTPase was added to the coupled system, two other locally stable states emerged, both having the tGTPase inactivated and being interpreted as having low active tGTPase concentrations. Finally, the addition of a second feedback loop, from the active tGTPase to the GAP of the mGTPase, gives rise to a family of steady states that can be parametrized by a range of inactive tGTPase concentrations. Our findings reveal that the coupling of these two different GTPase motifs can dramatically change their steady state behaviors and shed light on how such coupling may impact signaling mechanisms in eukaryotic cells.

Logical identification of all steady states: The concept of feedback loop characteristic states

1993 ◽  
Vol 55 (5) ◽  
pp. 973-991 ◽  
Author(s):  
Houssine El Snoussi ◽  
Rene Thomas
Keyword(s):  
Feedback Loop ◽  
Steady States

Global metabolic changes following loss of a feedback loop reveal dynamic steady states of the yeast metabolome

2007 ◽  
Vol 9 (1) ◽  
pp. 8-20 ◽  
Author(s):  
Peng Lu ◽  
Anupama Rangan ◽  
Sherwin Y. Chan ◽  
Dean R. Appling ◽  
David W. Hoffman ◽  
...  
Keyword(s):  
Feedback Loop ◽  
Steady States ◽  
Metabolic Changes

Novel players fine-tune plant trade-offs

2015 ◽  
Vol 58 ◽  
pp. 83-100 ◽  
Author(s):  
Selena Gimenez-Ibanez ◽  
Marta Boter ◽  
Roberto Solano
Keyword(s):  
Ubiquitin Ligase ◽  
Feedback Loop ◽  
Molecular Level ◽  
26S Proteasome ◽  
Signalling Molecules ◽  
Transcriptional Reprogramming ◽  
Trade Offs ◽  
Jaz Proteins ◽  
Regulatory Feedback Loop ◽  
Fine Tune

Jasmonates (JAs) are essential signalling molecules that co-ordinate the plant response to biotic and abiotic challenges, as well as co-ordinating several developmental processes. Huge progress has been made over the last decade in understanding the components and mechanisms that govern JA perception and signalling. The bioactive form of the hormone, (+)-7-iso-jasmonyl-l-isoleucine (JA-Ile), is perceived by the COI1–JAZ co-receptor complex. JASMONATE ZIM DOMAIN (JAZ) proteins also act as direct repressors of transcriptional activators such as MYC2. In the emerging picture of JA-Ile perception and signalling, COI1 operates as an E3 ubiquitin ligase that upon binding of JA-Ile targets JAZ repressors for degradation by the 26S proteasome, thereby derepressing transcription factors such as MYC2, which in turn activate JA-Ile-dependent transcriptional reprogramming. It is noteworthy that MYCs and different spliced variants of the JAZ proteins are involved in a negative regulatory feedback loop, which suggests a model that rapidly turns the transcriptional JA-Ile responses on and off and thereby avoids a detrimental overactivation of the pathway. This chapter highlights the most recent advances in our understanding of JA-Ile signalling, focusing on the latest repertoire of new targets of JAZ proteins to control different sets of JA-Ile-mediated responses, novel mechanisms of negative regulation of JA-Ile signalling, and hormonal cross-talk at the molecular level that ultimately determines plant adaptability and survival.

A miR-29a-driven negative feedback loop regulates the glucocorticoid receptor in health and disease

2018 ◽  
Author(s):  
C Glantschnig ◽  
M Koenen ◽  
M Gil Lozano ◽  
M Karbiener ◽  
CL Cummins ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Negative Feedback ◽  
Feedback Loop ◽  
Negative Feedback Loop ◽  
Health And Disease

Inhibitory Feedback Loop Induces Anticipated Synchronization in Neuronal Networks

2014 ◽  
Vol 1 ◽  
pp. 636-639
Author(s):  
Fernanda S. Matias ◽  
Pedro V. Carelli ◽  
Claudio R. Mirasso ◽  
Mauro Copelli
Keyword(s):  
Feedback Loop ◽  
Neuronal Networks ◽  
Inhibitory Feedback
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