signaling cascade
(noun)
the chain of events that conveys the signal through the cell
Examples of signaling cascade in the following topics:
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Termination of the Signal Cascade
- Signal cascades convey signals to the cell through the phosphorylation of molecules by kinases.
- The chain of events that conveys the signal through the cell is called a signaling pathway or cascade.
- A major component of cell signaling cascades is the phosphorylation of molecules by enzymes known as kinases.
- Inside the cell, many different enzymes reverse the cellular modifications that result from signaling cascades.
- Describe the process by which the signal cascade in cell communication is terminated
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Signaling in Yeast
- Yeasts utilize cell-surface receptors, mating factors, and signaling cascades in order to communicate.
- The components and processes found in yeast signals are similar to those of cell-surface receptor signals in multicellular organisms.
- When mating factor binds to cell-surface receptors in other yeast cells that are nearby, they stop their normal growth cycles and initiate a cell signaling cascade that includes protein kinases and GTP-binding proteins that are similar to G-proteins.
- Because yeasts contain many of the same classes of signaling proteins as humans, these organisms are ideal for studying signaling cascades.
- Therefore, the signaling cascades are also simpler and easier to study, although they contain similar counterparts to human signaling
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Binding Initiates a Signaling Pathway
- Ligand binding to cell-surface receptors activates the receptor's intracellular components setting off a signaling pathway or cascade.
- After the ligand binds to the cell-surface receptor, the activation of the receptor's intracellular components sets off a chain of events that is called a signaling pathway or a signaling cascade .
- The effects of extracellular signals can also be amplified by enzymatic cascades.
- However, activation of a receptor-linked enzyme can activate many copies of a component of the signaling cascade, which amplifies the signal.
- A complex cascade of downstream events causes the cell to grow and divide.
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Synaptic Plasticity
- Next, Ca2+ ions entering the cell initiate a signaling cascade that causes a different type of glutamate receptor, AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptors, to be inserted into the postsynaptic membrane.
- In this situation, calcium that enters through NMDA receptors initiates a different signaling cascade, which results in the removal of AMPA receptors from the postsynaptic membrane .
- This stimulation causes a calcium- and CaMKII-dependent cellular cascade, which results in the insertion of more AMPA receptors into the postsynaptic membrane.
- The calcium that does flow through NMDA receptors initiates a different calcineurin and protein phosphatase 1-dependent cascade, which results in the endocytosis of AMPA receptors.
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Cell Signaling and Cell Death
- External signaling can also initiate apoptosis.
- The binding of cellular receptors to the extracellular matrix initiates a signaling cascade within the cell.
- However, if the cell moves away from the extracellular matrix, the signaling ceases, and the cell undergoes apoptosis.
- Another example of external signaling that leads to apoptosis occurs in T-cell development.
- A cell signaling mechanism triggers apoptosis, which destroys the cells between the developing digits.
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Mechanisms of Hormone Action
- Cellular recipients of a particular hormonal signal may be one of several cell types that reside within a number of different tissues; This is so in the case of insulin, which triggers a diverse range of systemic physiological effects.
- Different tissue types may also respond differently to the same hormonal signal.
- As a result, hormonal signaling is elaborate and hard to dissect.
- Relay and amplification of the received hormonal signal via a signal transduction process.
- Water-soluble hormones such as Epinephrine, bind to a cell-surface localized receptor, initiating a signaling cascade using intracellular second messengers.
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Gene Expression for Spatial Positioning
- During development it is critical that specific gene expression patterns are established to signal and differentiate the cells appropriately.
- The process of differentiation is regulated by cellular signaling cascades.
- During the formation of the neural system, special signaling molecules called growth factors signal some cells at the edge of the ectoderm to become epidermis cells.
- If the signaling by growth factors were disrupted, then the entire ectoderm would differentiate into neural tissue.
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Programmed Cell Death
- Apoptosis can also be initiated via external signaling.
- The binding of cellular receptors to the extracellular matrix initiates a signaling cascade within the cell.
- However, if the cell moves away from the extracellular matrix, the signaling ceases, and the cell undergoes apoptosis.
- Another example of external signaling that leads to apoptosis occurs in T-cell development.
- A cell signaling mechanism triggers apoptosis, which destroys the cells between the developing digits.
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Methods of Intracellular Signaling
- The induction of a signaling pathway depends on the modification of a cellular component by an enzyme.
- Phosphorylation of tyrosine residues can either affect the activity of an enzyme or create a binding site that interacts with downstream components in the signaling cascade.
- They are small molecules that propagate a signal after it has been initiated by the binding of the signaling molecule to the receptor.
- Phosphatidylinositol (PI) is the main phospholipid that plays a role in cellular signaling.
- Explain how the binding of a ligand initiates signal transduction throughout a cell
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Types of Cytokines Participating in Immune Response
- Cytokines are small cell-signaling protein molecules that are secreted by numerous cells.
- Cytokines are small cell-signaling protein molecules that are secreted by numerous cells and are a category of signaling molecules used extensively in intercellular communication.
- Cytokines provide the signaling pathways that orchestrate the complex immune responses of the human body.
- Cytokines are similar to hormones, which are also chemical messengers, however hormones have considerably more variation in molecular structure, and are involved more in tissue signaling than cellular signaling.
- Subsequent cascades of intracellular signalling then alter cell functions.