Questions tagged [cell-signaling]

Tag for questions related to the process of cells receiving a stimulus from its environment, or from itself (autocrine signaling), and responding as a result of the stimulus.

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What is a polar plot of relative neural firing

I am taking my PhD qualifying exams on monday, and there is a seemingly simple practice problem that I can't seem to figure out, and I was hoping someone here would have some knowledge, or at least be ...
Brian's user avatar
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Are there any good demonstrations of phosphorylation cascades?

So I'm working on this 2D signal transduction pathway computer simulation, and I'm struggling to grasp this process of protein kinases phosphorylating each other over and over again during the "...
Ege Gürsel's user avatar
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What is meant by the steady-state activation of a receptor?

I am reading a journal paper about the insulin-like growth factor 1 receptor. In this paper, there is the following statement: Finally, we show that the IGF-IR and the PI3K subunit p85 and Akt are ...
ceno980's user avatar
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Do we know how the different functions are selected when Wnt pathway is activated?

The Wnt signaling pathway is said to allows multiple functions: Axis patterning Cell differentiation Cell proliferation Cell fate specification Cell migration But how are these functions "...
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What cells are secreting Wnt pathways and under which conditions?

Former question: Where and how happen these operations in the Wnt signaling pathway? I have read about the signaling pathway on wikipedia: Wnt comprises a diverse family of secreted lipid-modified ...
totalMongot's user avatar
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How is bio electricity modulated experimentally? [closed]

In the research performed by Micheal Levin et al, the morphological changes induced by changes in bio electricity are well demonstrated, most strikingly in his experiments in planarian worms. Yet ...
Evamentality's user avatar
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Why doesn't the cell just use one messenger?

I recently learned the second messenger model, where adrenaline activates adenyl cyclase, which converts ATP into cAMP. Then cAMP acts as a second messenger which activates portein kinase enzymes. The ...
Bruce M's user avatar
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Receptor tyrosine kinases: What does "tonic activation", "tonic inhibition" and "tonic brake" mean?

I am reading a journal paper about the insulin receptor (IR). The insulin receptor is a receptor tyrosine kinase, and upon ligand binding, undergoes autophosphorylation of intracellular tyrosine ...
ceno980's user avatar
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Receptor tyrosine kinases: What is meant by basal phosphorylation of the receptor?

I am reading a journal paper about the insulin receptor. The insulin receptor is a receptor tyrosine kinase, and upon ligand binding, undergoes autophosphorylation of intracellular tyrosine residues. ...
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Molecular Signaling: Why is it more difficult to study membrane-bound signaling molecules compared to soluble ones?

I am reading the textbook Neuroscience (6th ed.) by Dale Purves and colleagues. In one of the chapters (Chapter 7, Molecular Signaling within Neurons), I am reading about the different types of ...
ceno980's user avatar
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Resources for understanding the basics of cell signaling, gene expression and cell fate determination, for a physics student?

I'm a physics student who will join a theoretical biology/applied mathematics research group this September. I'll link some papers at the end for further context. The main problem I have is that my ...
agaminon's user avatar
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Examples of natural graded transcriptional responses to extracellular ligands

In this paper (1) from 2001 the authors show that the mating pathway in budding yeast yields a graded transcriptional response to increasing concentrations of pheromone, and claim that: To our ...
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The quality of binding sites?

Can someone please provide a human friendly explanation. to the following: RNAp binds a defined site (a specific DNA sequence) at the promoter (Fig- ure 2.2a). The quality of this site specifies the ...
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Is Signal Transduction Unidirectional from the Stimuli to the Final Receptor?

I wonder if signal transduction in biological systems including visual, olfactory, tactile or any other biological system, is unidirectional. Suppose that $X_i$ is the $ith$ cell in the signal ...
Ali Pedram's user avatar
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What would happen to the membrane potential if a cell didn't have developed relative refractory period?

If the Na+ voltage gated channels remain open instead of getting deactivated during the re-polarization period, would the membrane potential become 0 since the Na+ ions would be constantly bringing ...
uwuwubread's user avatar
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How does NaF protect G proteins from denaturation?

Below is presented Figure 4 from the 1977 paper of Ross and Gilman, which provided evidence for the existence of G proteins: The protocol (and rationale) is as follows: Wild-type cell membranes was ...
Anon Emouse's user avatar
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How do the maximum rates of calcium pumping compare between the calcium ATPases SERCA and PMCA

Two important Calcium ATPases found within cells are the Sarcoplasmic reticulum Ca2+ ATPase (SERCA) and the Plasma membrane Ca2+ ATPase (PMCA). Both use ATP to help maintain resting calcium ...
BioPhysicist's user avatar
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At what calcium concentration does the Sodium-Calcium Exchanger (NCX) "turn on"?

I am interested in the comparison between the Plasma Membrane Calcium ATPase (PMCA) and the Sodium-Calcium Exchanger (NCX) which are two pumps on the plasma membrane of cells that serve to move ...
BioPhysicist's user avatar
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Can a constitutively active kinase be highly regulated?

I am studying the protein kinase GSK3 and I am learning about the regulation of its activity. Many journal papers that I have read have stated that GSK3 is unique because it is a constitutively active ...
ceno980's user avatar
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Why hypothyroidism causes body ache?

In the condition of hypothyroidism the Thyroid Stimulating Hormone level is high in individuals. What signalling/metabolic pathway mediates this sensation of pain which is mostly experienced in feet ...
Sucharita Chatterjee's user avatar
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How to convert cell units (c.u.) to mole?

If one has values in terms of cell units (c.u.) how may it be converted to $\mu$M? Should I think a "cell unit" as $1\;c.u.= \frac{1}{\text{cell volume}}$ and $1\;c.u.=\frac{1}{\text{cell ...
confused's user avatar
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Are there any online resources for finding the signaling pathways that two proteins both belong to?

I am studying the proteins GSK3 and AMPK and I am trying to identify the signaling pathways that both of these proteins belong to. From reading journal papers I have found out that both of these ...
ceno980's user avatar
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What does it mean to "nucleate multi-protein complexes"?

I am reading an article about the mTOR signalling pathway and I have come across the following: mTOR nucleates at least two distinct multi-protein complexes, mTOR complex 1 (mTORC1) and mTOR complex ...
ceno980's user avatar
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How are neurons selective towards specific stimuli?

I've read several papers that mention that there are specific neurons that are activated for specific things (e.g. neuron A activate only when horizontal lines appear, neuron B activate when certain ...
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2nd messenger mechanisms [duplicate]

Many hormones use 2nd messenger mechanisms, such as cAMP and cGMP, and also act on the same cells. For example calcitonin and PTH both use cAMP and have opposite effects. How is it possible that the ...
Vishnu 's user avatar
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Absence of cytoplasmic Intermediate Filaments in Arthropods

Cytoplasmic intermediate filaments such as vimentins support the architecture of the cell and have been known to aid signaling processes. However, as in this article, it is stated that out of all ...
Rishika Sharma's user avatar
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1 answer
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In a skeletal muscle contraction, what happens after ACh binds to the nicotinic iontropic receptors on sarcolemma?

Does the bound ACh becomes unbound and then gets hydrolysed by acetylcholinerase?
電急流光's user avatar
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What are " temporal kinetics"?

I am new to Biology and I am reading some papers about kinase proteins. I know what kinases do in the body. However, I found it hard to understand what are "kinetics". I googled this term ...
Adel's user avatar
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Time scale for cAMP-dependent pathway cascades

What is the time scale for cAMP-dependent pathway cascades that start at the level of ligand binding to a G-protein receptor and finish at the level of gene transcription regulation? For example, when ...
S.C.'s user avatar
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Alzheimer's disease - Hyperexcitability

I am trying to read literature on Alzheimer's disease. A very important phenomenon that occurs in AD patients, is hyperexcitability in neurons close to A-beta concentrations. Some authors only ...
axel's user avatar
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What are some good books on basics of Cell signaling?

I think the title says it all. (self answered, although others' answers requested)
Always Confused's user avatar
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How are newly synthesised proteins targeted to the plasma membrane?

There does not seem to be a definitive answer to how proteins destined to be intrinsic plasma membrane proteins are directed there. Presumably, assuming starting at a cytosolic ribosome, the pathway ...
pincushion44's user avatar
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1 answer
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How do tumor cells 'gravitate' towards each other?

In a popular article it is mentioned that in centrifugal experiments with cancer cells that When subjected to microgravity-conditions, the cancer cells were unable to sense each other and therefore ...
AtmosphericPrisonEscape's user avatar
6 votes
4 answers
4k views

What do the the different arrowheads mean in a cell signalling diagram?

What do the different arrowheads mean in the figure below? Are there arrows upstream or downstream signalling?
Tom's user avatar
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1 answer
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How do we know if a neuron is inhibitory or excitatory?

The textbook examples for an excitatory neurotransmitter is Glutamate, and for an inhibitory neurotransmitter it is GABA. In my naive understanding, a neuron was inhibitory or excitatory depending on ...
Pugl's user avatar
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How do receptors lose their sensitivity?

Recently, I learned that one of the causes of Type II diabetes is that insulin receptors on cell surfaces lose their sensitivity due to long-term high exposure to insulin (which occurs as a result of ...
F16Falcon's user avatar
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1 vote
1 answer
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Why do many cells together survive better than one cell alone?

I know that one cell with no ECM is subject to anoikis. That's why in general one cell alone not in its environment is dying. But are there advantages for a cell to live close to other cells even of ...
J.A's user avatar
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Spatially Encoded GPCRs?

I'm reading this paper, and I'm already lost in terms of what they mean by GPCR signaling is spatially encoded. The trafficking of G protein coupled‐receptors (GPCRs) is one of the most exciting ...
user3665690's user avatar
2 votes
0 answers
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What regulates cyclic AMP?

After reading a textbook chapter on GPCRs I am still confused by what regulates cAMP. I took in my notes that cAMP is made by adenylyl cyclase and destroyed by cAMP phosphodiesterases (also another ...
user3665690's user avatar
6 votes
3 answers
414 views

How do DNA, enzymes, hormones etc. reach their proper cellular locations?

I was trying to understand DNA transcription from this chapter, and there seems to be no explanation on how exactly the proteins, enzymes and other molecules manage to find each other inside the cell. ...
Nav's user avatar
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Exporting RNA in extracellular vesicles (exosomes)?

I'm interested in how much is know about the process by which RNA is secreted from cells into extracellular vesicles. Where is a good place to start reading about this? How much is known about this ...
libby's user avatar
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1 answer
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Why is inhibition of inhibition (reciprocal inhibition) such a common motif in cell signalling?

In transcriptional regulation, you often find that positive signals proceed by inhibiting or destroying a protein that is in turn inhibiting or destroying the effector protein. This can be seen in the ...
ooakley's user avatar
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2 votes
0 answers
415 views

Why is erythropoietin produced in the kidney?

Erythropoietin is a hormone produced in the kidney to stimulate the generation of more red blood cell. It is triggered by low oxygen via HIF transcription factors. Makes sense. Oops, oxygen is low, ...
SeanJ's user avatar
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4 votes
1 answer
108 views

Is there a reason for the lack of full RTK structures?

Bocharov et al. (2013) write that As there are no structures of full-length RTKs [receptor tyrosine kinases], we do not fully understand how different domains function together to mediate signal ...
orthocresol's user avatar
3 votes
1 answer
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What is the difference between a cytokine, a hormone and a protein hormone?

I'm trying to figure out the difference between hormone, cytokine and protein hormone. It's clear to me that all three are biological messengers, but there seems to some ambiguity and overlap between ...
Dianne's user avatar
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2 votes
1 answer
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T-Cell Motility: does motility require direction specific actin polymerization?

T-cells have been shown to migrate inside concentration gradients - both in the direction of the source or away. Even under shallow gradients, t-cells move. I argue that, to be able to move in a ...
Eric McGhee's user avatar
2 votes
1 answer
249 views

Is every neurotransmitter receptor an ion channel?

This is a rudimentary question--perhaps the answer is well known to biologists, but is every neurotransmitter receptor also an ion channel? For example, NMDAR is a glutamate receptor and cation ...
wanderingmathematician's user avatar
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Why inhbition of RTK will not help in a case of mutant EGF?

I was given the following as an example for a quiz question but i don't understand the answer. Any help will be most welcome: Question: Iressa is a Tyrosine Kinase Inhibitor. As a young oncologe, to ...
user135172's user avatar
1 vote
1 answer
4k views

What is the difference between Integrin to Cadherin?

My question is probably very basic but i couldnt get it in lecture and not from looking in the net. What is the difference between Integrin to Cadherin. By difference I am looking for say: ...
user135172's user avatar
1 vote
0 answers
32 views

How does the Lgr5 receptor contribute to maintaining stemness in the intestine?

I don't understand the connection between Lgr5 receptor and Wnt between Paneth cells and stem cells. And how does this link to the EphB-EprinB inhibition between transit amplifying cells and ...
Thale Mathiassen's user avatar