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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E. coli & aspartate

I am familiar with the linkage between aspartate/ligand binding, receptor methylation, and flagellar behavior re. style of locamotion, but I do not know what the bacterium does with the aspartate it ...
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25 views

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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1answer
60 views

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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65 views

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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40 views

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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Examples of GDP (rather than GTP) activating cell signalling?

Is there any known example in a cell where a protein is activated by the hydrolysis of GTP to GDP, rather than the reverse in which a protein is activated when GTP binds to an inactive GDP-bound ...
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171 views

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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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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3answers
225 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. ...
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54 views

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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44 views

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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367 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, ...
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1answer
67 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 ...
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1answer
743 views

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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1answer
45 views

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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185 views

How can calcium be a kept as a local signal in the cytoplasm?

We went through this in my class last week and it doesn't make sense to me at all. It's small and it diffuses in and out so easily so wouldn't it diffuse out quickly and thus not be a local signal? ...
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1answer
73 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 ...
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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, ...
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1answer
350 views

Do two hormones have the same effect on a cell if the second messenger is the same?

There are so many hormones/cytokines/neurotransmitters and receptors, all of which act through about 4-5 second-messenger systems. So if one particular cell has receptors for say, two different ...
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1answer
2k 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: ...
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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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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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1answer
51 views

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 “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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1answer
69 views

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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4k views

Why is insulin given in type 2 diabetes?

For this reason "insulin insensitivity", or a decrease in insulin receptor signaling, leads to diabetes mellitus type 2 – the cells are unable to take up glucose, and the result is hyperglycemia (an ...
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41 views

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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108 views

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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1answer
116 views

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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1answer
79 views

Signaling between Organelles

I'm confused about how organelles communicate with each other. I understand signaling between cells and the whole transcription and translation of DNA process. However, how does a motor protein know ...
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66 views

Is there a measurable variance in neuronal transmission speed and fidelity?

My understanding of how neurons transmit signals is pretty basic - dendrites receive signals (both excitatory and inhibitory), transmitting them to the cell body where, if a sufficient depolarization ...
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2answers
3k views

Why does Hunger lead to the aggressive behavior?

I have observed that frequently when people are hungry; they tend to get angry more easily on pointless issues. Does this mean that our fight or flight response is more active when a person is hungry? ...
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1k views

Exact definition of 'convergent' and 'divergence' in cell signalling?

From what I understand, we refer to 'signal convergence' as being when two different ligands/stimuli lead to the same (at least in part) responses inside a single cell. This may or may not be due to ...
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1answer
55 views

How many molecules are generally required for cell signallng processes for given cases?

I know its really a broad topic but I am interested in just few cases: Quorum sensing neurotransmitters for the communication of images/ general information hormones/pheromones I actually want to ...
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1answer
73 views

Is Sda a protein, or is it a protein domain of DnaA?

I initially thought that a domain was a specific part of a protein, with it given tertiary structure, to which a given molecule is able to bind. (I think I recall phrases such as "the haem binding ...
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666 views

Advantages and disadvantages of sporulation compared with competence in bacteria?

Why do bacteria have both of these mechanisms to deal with the same environmental stress: nutrient deprivation? In a culture exposed to this condition, often both competent cells and sporulated cells ...
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Specificity in MAPK/ERK pathway and PC12 Cells

Background PC12 Cell stimulation leads to distinct outcomes upon stimulation with either EGF or NGF (epidermal and nerve growth factors). The outputs are transmitted through the MAPK/ERK signaling ...
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831 views

Hedgehog AP Bio question

Could someone please explain this AP Biology question? I know the answer is C but I do not understand why. Doesn't Smo prevent gene transcription? If you "block its activity" then wouldn't it cause ...
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695 views

Where and how is information about pathogen immunity stored in a cell?

If all of the DNA is being used, then how would the cell be able to store new information about pathogens in DNA? It's like a full hard drive that can't hold any more. So does the cell just compress ...
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1answer
152 views

Why are truncations in Receptor Tyrosine Kinases so sommon in transformations?

Receptor Tyrosine Kinases (RTKs) present themselves on the surface of a cell as monomers until a ligand (such as a mitogen) binds and causes the formation of the active dimer. However I do not ...
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32 views

Terminology for quantitative response of T cells to antigen complexes

In the article, there is a statement which is: Although DCs are remarkably efficient in evoking T cell responses with few antigen– MHC complexes (1–100 per DC) (1–3), they must first ...
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954 views

How do chameleons signal cells to change color?

I have read about how they can change color, but is there literature about the chemical signaling process they use to do so? I read that it could be some combination of hormones and neurotransmitters,...
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What is the step by step procedure that leads the T cell to release chemokines?

When T cell receptors bind to the receptor of an antigen presenting cell, is this what leads to the release of chemokines? I know that T cell release of chemokines leads to the migration of other T ...
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155 views

Retrograde/anterorade transport; kinesin/dynein; COP1/COP2; Endoplasmic reticulum/Golgi

I am getting slightly confused with all of the terms above and was wondering if someone could see if I have got this right: I think transport from the ER to Golgi is almost always from the plus end ...
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767 views

Is the signal peptide always cleaved during protein synthesis in the ER?

My university supervisor said that the signal sequence is always cleaved, however my text book differs. What I gather from my text book (though it isn't very clearly stated so i'm not sure) is that: ...
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591 views

How do cells determine what size to grow to before dividing? [closed]

How do cells determine size to grow to before dividing?
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196 views

Do all plant hormones of one group show the same qualitative effect with respect to their target pathway(s) and the biological response?

I wonder, terms like "Auxin", "Cytokinin", "Gibberellin" etc means NOT a single compound; but a class of compound. For example "Auxin" does-not mean a single compound, but several compounds such as :...
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How exactly apoptosis starts? [closed]

I read article about apoptosis on Wikipedia, but didn't understand, how exactly the organism learns that it is necessary to launch process of apoptosis in certain cell. In other words, on what signs ...