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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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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?
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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 ...
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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 ...
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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 ...
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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)
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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 ...
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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 ...
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4 answers
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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?
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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3 answers
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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. ...
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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 ...
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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 ...
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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, ...
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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 ...
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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 ...
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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 ...
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2 votes
1 answer
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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 ...
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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 ...
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1 answer
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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: ...
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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 ...
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3 votes
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What is the purpose of Prostaglandin F2-alpha and the Prostaglandin F receptor in the melatonin cell signaling pathway?

I've been doing a lot of research recently on the melatonin cell signaling pathway for an extra credit project at school. I've included an image in this post, which is a diagram of the MT1 pathway. It ...
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1 answer
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How does cell detect if a RNA polymerase II is stalled during transcription and in turn deploy the proper transcription-coupled repair factors?

When a segment of the template strand of DNA is damaged due to factors such as UV radiation, a lesion is created that would effectively block the passage of RNA polymerase II during transcription. ...
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Does a cell deprived of growth factors undergo apoptosis or G0 stasis?

I can't seem to find a decisive answer on this topic in any of my textbooks. If a cell is deprived of growth factors does it: Activate apoptosis Go into the G0 phase but keep living? Thanks.
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How do cells relocate transmembrane proteins from one side of the cell to the other? Is it possible?

Is there a process by which cells can relocate proteins residing on the cell membrane in areas of low demand to that of a high demand location somewhere else in on the cell? What's that process called?...
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Does "eating less" stimulate cell starvation?

2016 Nobel Prize in physiology or medicine was given for the study of autophagy. Judging from the description, a healthy cell responds to starvation (and other types of stress) with autophagy. Does ...
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How do cell signaling ensures time synchronization?

Let us suppose two cells A and B communicating with one another, I want to know how do cells ensure time synchronization while communicating. For instance, let us assume cell A sends a sequence '110'. ...
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How do photoreceptors overcome the ambiguity of wavelength vs intensity to determine brightness? [duplicate]

I asked a similar question about the Principle of Univariance yesterday, but now I have another one. According to the Principle of Univariance, the input to a photoreceptor differs along two ...
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1 answer
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Do cells communicate only in binary levels?

In modern communication we generally have various schemes to communicate the given signal, one of them is to convey information with different levels. does cell signaling too have levels apart from ...
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What are these lines that connect into cells called?

I just recently watched a very interesting video that showed cell division under a microscope. In the video, you can see cells that have either one, two or more lines connected to them. What are these ...
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What happens to those molecules that are not received by receptor proteins on the cell membrane?

I am studying cell communication and come to know that proteins from outside environment gets received by receptors on the cellular membrane and then the signal is transduced inside the cell. My ...
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1 answer
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Specific examples of signalling pathway using logical 'OR' and 'AND'?

I have read here that "signals from two different pathways may be needed to activate a response, which is like a logical "AND." Alternatively, either of two pathways may trigger the same response, ...
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