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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12
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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? ...
8
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1answer
609 views

If so many different hormones/molecules work by activating adenylyl cyclase, how do they have different effects?

It seems that many hormones and molecules work by activating adenylyl cyclase to convert $\text{ATP}$ to $\text{cAMP}$, such as adrenaline and glucagon. Both of these seem to bind to $\text G$ protein ...
7
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2answers
955 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,...
7
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1answer
2k views

Cat purring: What are some possible underlying mechanisms behind purring and bone remodeling and formation?

http://www.scientificamerican.com/article.cfm?id=why-do-cats-purr The article above says that cats purr mostly when they're wounded or under duress. They hypothesis that cats purring leads to ...
6
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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. ...
6
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1answer
2k views

How do steroids travel in the bloodstream?

Cholesterol, which is hydrophobic, cannot simply travel in the bloodstream, and instead is enclosed in lipoprotein (LDL, HDL). Steroids, which are derived from cholesterol, are also hydrophobic (right?...
6
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4answers
422 views

Exocytosis of mast cell secretory granules

I've been doing a bit of reading about mast cell degranulation and have become thoroughly lost while trying to understand how the secretory granules are actually secreted. I understand that there are ...
6
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2answers
1k views

Question about cell signaling pathways (RTK, Jak-Stat, SMAD, etc)

I am in an embryology course right now and we've just started covering cell-cell communication in development. We were talking about the roles of the various cadherins and their discoveries but we got ...
6
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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 ...
6
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1answer
449 views

Models of quorum sensing for multi-agent systems

Quorum sensing is a system of stimulus and responses correlated to population density that is used by bacteria to coordinate gene-expression. I am looking for a simple computational/mathematical model ...
6
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2answers
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? ...
5
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4answers
301 views

Specificity of Protein Kinases in Signaling Pathways..?

In most of the signaling pathways the activated receptor when activates Protein Kinase through the action of secondary messenger, then these protein kinases almost always phosphorylate on the specific ...
5
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3answers
694 views

How can a ligand be an integral membrane protein?

My background is in mathematics, and not biology, so please bear with me. I am currently working on a project involving the effects of Epidermal growth factor treatment (EGF) on cell migration. I am ...
5
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2answers
2k views

Effect of steroid hormone on specific cells?

As steroid hormones can pass through the plasma membrane by simple diffusion because they are lipid derived hormones, it means that they are capable of passing through every cell of our body, BUT why ...
5
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2answers
18k views

Explanation of the terms “downstream signaling” and “upstream signaling”

In molecular biology, what's the meaning of the terms "downstream signaling" and "upstream signaling"? What's the difference between them?
5
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1answer
763 views

Why does a “cascade” of events happen during signal transduction?

I've been watching some videos on signal transduction and it says that because there are enzymes being activated by the signal, then there is a "cascade" which happens afterwards...I don't understand ...
5
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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, ...
5
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1answer
70 views

What's the duration between the binding of adrenaline to β-AR and the first translated protein?

Binding of adrenaline (epinephrine) to the β-Adrenergic receptor leads to formation of cAMP (via G protein activation), activation of protein kinase A and subsequently to the expression of specific ...
4
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2answers
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?...
4
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2answers
727 views

Effect of testosterone hormone on cell signalling and behaviour?

A steroid, testosterone was injected in female body which led to development of secondary sexual characters but these characters were not developed over night (Response was very slow). What could be ...
4
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2answers
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 ...
4
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1answer
206 views

What happens to IP3 molecules after release from IP3 receptors?

IP3 molecules bind to IP3 receptors and open up the calcium channels on the endoplasmic reticulum. I am wondering what happens to IP3 molecules after they have been released from the IP3 receptor? Do ...
4
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1answer
605 views

which signalling pathway is involved in cancer?

Columnar epithelial cells from the colonic mucosa are studied to identify abnormalities in cell signaling pathways. Abnormal epithelial cells from colonic adenocarcinoma are shown to have a mutation ...
4
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2answers
504 views

Signaling through G protein Coupled Receptors?

There are two different cell lines but we do not know that these cell lines have Gs or Gi proteins, associated with their G-protein coupled receptors. If we wants to know about this. Can we design a ...
4
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1answer
972 views

Significance of lipids in biological membranes…?

Membranes are specifically designed by lipids to maintain internal hydrophilic environment in narrow range.There are hydrophobic amino acids among naturally occurring 20 amino acids and as well as ...
4
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1answer
232 views

Amino acid profile of GPCRs

You are studying cellular signalling through a newly identified GPCR. Specifically you’re working on a pair of newly identified GPCRs, GPCR-A and GPCR-B. Each binds the same small ligand, but ...
4
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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 ...
4
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0answers
242 views

What is the essence of difference of how different chemicals affect the same receptor?

It is known that various chemicals can bind to the same receptor type, producing different effects. Be these chemicals agonists or antagonists, there are more variations in how they influence the ...
4
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0answers
97 views

When and How do pacemaker cells develop during the cell aggregation process of Dictyostelium discoideum?

I was reading a paper by Tang & Othmer about oscillations and waves in Dictyostelium discoideum. Under certain condition like starvation period in the life cycle of a Dictyostelium discoideum ...
3
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3answers
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 ...
3
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1answer
519 views

How do GPCRs transmit a signal across the plasma membrane?

How do G-coupled protein receptors (GPCR) transmit signals through the plasma membrane? Links containing information about this and pictures will be very helpful.
3
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2answers
394 views

Does the cellular response to every receptor work the same way?

I heard somewhere that activating any receptor results in the same intracellular response (signaling) which involves NF-κB. If that is true, I hardly understand how the cells distinguish between ...
3
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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 ...
3
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1answer
352 views

How do axon terminals report to the soma?

It is important to bear in mind that the distance between a neuron's axon terminal and its soma can be extensive, up to about 1m in the human body. The fastest transport along the axon is 400mm/day (...
3
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2answers
1k views

How does the cell regulate different metabolic pathways?

I heard somewhere that cells use different nucleosides bound to triphosphates e.g. ATP, GTP, CTP and other modified compounds: NADH, NADPH to distinguish between different metabolic pathways and so ...
3
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0answers
126 views

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 ...
3
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0answers
102 views

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 ...
3
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0answers
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 ...
3
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0answers
110 views

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 ...
2
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1answer
1k views

Meaning of “auto” in trans autophosphorylation?

Why this process called "auto"? Is it because each tyrosine kinase receptor subunit of the RTK dimer has the ability to phosphorylate tyrosine or other amino acid residue present in other subunit of ...
2
votes
1answer
749 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 ...
2
votes
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 ...
2
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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 ...
2
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2answers
508 views

Localization of Protein Kinase-A

Is protein kinase-A located in the cytosol/cytoplasm of cells or in the plasma membrane? Also, is it considered a receptor molecule since it is dependent on cAMP? Any and all help is appreciated. ...
2
votes
1answer
621 views

What is the functional significance of the difference in cardiolipin/cholesterol ratio in different membranes?

I have read somewhere that the plasma membrane has little cardiolipin but excess cholesterol whereas the inner mitochondrial membrane is rich in cardiolipin and has little cholesterol.I just wanted to ...
2
votes
1answer
164 views

Why do oncogenes show genetic dominance?

As we know that tumor suppressor gene causes cancer only when both the alleles are recessive in nature.But in case of oncogenes if only one allele is dominant it can cause cancer.Why in case of ...
2
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1answer
109 views

Structure of biological membranes?

Integral membrane proteins have functional asymmetry i.e. they have two different domains of proteins performing different functions. these proteins have Tyr and Trp amino acid residues at the ...
2
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1answer
972 views

What is a mechanical cue?

I was attending a talk related to neurogenesis. So one professor was asking a question related to biochemical cues and mechanical cues (related to signaling pathways I believe). Cue as far as I ...
2
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1answer
304 views

Can (any) human cells learn?

I'm not talking about single celled organisms, but actual cells in your body. Is there any evidence that they can learn to, say, navigate an environment or avoid an aversive stimulus like an animal ...
2
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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 ...