Campbell Chapter 11 - Cell Communication

External signals

Signals that come from the environment outside of the cell.

Reception

The process in which a signaling molecule binds to a receptor protein, causing it to change shape.

Transduction

Cascades of molecular interactions that relay signals from receptors to target molecules in the cell.

Response

The cellular activity or regulation that occurs as a result of cell signaling.

Apoptosis

Programmed cell death that integrates input from multiple signaling pathways.

Cell communication

The process by which cells signal to each other and interpret signals received from other cells and the environment.

Epinephrine

A signaling molecule (also called adrenaline) that triggers the fight-or-flight response in cells.

Signal transduction pathway

A series of steps that occur when a signaling molecule binds to a cell surface receptor, leading to a cellular response.

Quorum sensing

The ability of bacterial cells to detect and respond to signaling molecules secreted by other bacterial cells.

Evolution of cell signaling

The idea that cell signaling mechanisms evolved early in the history of life and have been conserved across diverse species.

Quorum sensing

The mechanism by which cells sense their own population density.

Antibiotic-resistant bacteria

Bacteria that are resistant to several types of antibiotics.

MRSA

Methicillin-resistant Staphylococcus aureus, a strain of antibiotic-resistant bacteria.

Toxin

A harmful substance produced by bacteria that can cause damage to cells and contribute to inflammation.

Synthetic peptides

Short proteins that have been proposed as potential inhibitors of quorum sensing in S. aureus.

Inhibitory peptides

Peptides that interfere with the quorum-sensing pathways in S. aureus.

Growth medium

The substance in which bacteria are grown in a laboratory setting.

Concentration of toxin

The amount of toxin present in a culture of S. aureus, measured in μmoles/mL.

Additive effect

The combined effect of two or more substances that is greater than the sum of their individual effects.

Quorum-sensing pathway

The pathway through which cells communicate and coordinate their behavior based on population density.

Antibiotic-resistant S

Infections caused by S. aureus bacteria that are resistant to common antibiotics.

Epinephrine

Also known as adrenaline, it is an animal hormone that triggers the "fight-or-flight" response in animals.

Glucose 1-phosphate

The sugar released from glycogen breakdown.

Glucose 6-phosphate

The compound formed when glucose 1-phosphate is converted by the cell.

Cytosolic enzyme

An enzyme located in the cytoplasm of a cell.

Glycogen phosphorylase

An enzyme responsible for glycogen breakdown.

Reception

The target cell's detection of a signaling molecule from outside the cell.

Transduction

The process in which the binding of a signaling molecule changes the receptor protein and initiates a cellular response.

Response

The cellular response triggered by the signal transduction pathway.

Signaling molecule

A molecule that carries a signal and binds to a receptor protein.

Receptor protein

A protein located at the cell's surface or inside the cell that binds to a signaling molecule.

Local signaling

Signaling that occurs between nearby cells.

Synaptic signaling

A type of local signaling that occurs in the animal nervous system, where neurotransmitter molecules are released and trigger a response in the target cell.

Hormonal signaling

Signaling that occurs over long distances in animals, where specialized cells release hormones that travel via the circulatory system to reach target cells.

Plant hormones

Molecules that act as signaling molecules in plants and regulate growth and development.

Signal transduction pathway

A series of steps that convert a signal from a signaling molecule into a cellular response.

Ligand

A molecule that specifically binds to another molecule.

Receptor protein

A protein that undergoes a change in shape upon binding to a ligand, enabling it to interact with other cellular molecules.

Signal receptors

Proteins located on the plasma membrane or inside the cell that bind to specific signaling molecules and transmit information from the extracellular environment to the inside of the cell.

G protein-coupled receptors (GPCRs)

The largest family of human cell-surface receptors, involved in crucial roles in biological systems.

Transmembrane receptors

Receptors that span the cell membrane and transmit signals from the extracellular environment to the inside of the cell.

Receptor tyrosine kinases

A type of transmembrane receptor that phosphorylates tyrosine residues and activates signaling pathways.

Ion channel receptors

Receptors that allow the passage of ions across the cell membrane in response to ligand binding.

Transduction

The stage of cell signaling that converts the signal into a form that can bring about a specific cellular response.

Signal transduction pathway

A sequence of changes in different molecules that relay the signal from the receptor to the cellular response.

Relay molecules

Molecules in the signal transduction pathway that transmit the signal from one molecule to another.

Cellular response

The specific activity triggered by the transduced signal, such as enzyme catalysis, cytoskeleton rearrangement, or gene activation.

Cell signaling

The process by which cells communicate with each other through the transmission of signals.

Regulation

The control and adjustment of cell signaling processes to ensure proper coordination with other cells and activities of the organism.

Termination

The ending of cell signaling processes to prevent prolonged or excessive cellular responses.

β2-adrenergic receptors

A type of G protein-coupled receptor that binds to adrenaline (epinephrine) and plays a role in various physiological processes.

Cholesterol

A molecule present in the cell membrane that interacts with G protein-coupled receptors and affects their structure and function.

Reception

The stage of cell signaling where a signaling molecule binds to a receptor protein, causing it to change shape.

G protein-coupled receptor (GPCR)

A cell-surface transmembrane receptor that works with the help of a G protein, a protein that binds the energy-rich molecule GTP.

G protein

A protein that binds to a GPCR and becomes activated when a signaling molecule binds to the receptor, leading to cellular responses.

Ligand

A signaling molecule that binds to a receptor, such as a GPCR or RTK, and triggers a cellular response.

Tyrosine kinase

An enzyme that catalyzes the transfer of a phosphate group from ATP to a tyrosine residue on a substrate protein.

Receptor tyrosine kinase (RTK)

A membrane receptor characterized by having enzymatic activity as a tyrosine kinase, involved in the transfer of phosphate groups to tyrosine residues.

Dimerization

The process in which two receptor monomers associate closely with each other, forming a complex known as a dimer.

Phosphorylation

The addition of a phosphate group to a molecule, such as a tyrosine residue on a receptor or a substrate protein, often as a result of enzymatic activity.

Cell-surface receptors

Proteins found on the surface of cells that play important roles in cell signaling and are associated with various human diseases.

X-ray crystallography

A technique used to determine the three-dimensional structure of molecules, including cell-surface receptors.

GPCR

Stands for G-protein coupled receptor, a type of cell-surface receptor that plays a key role in cell signaling.

Receptor tyrosine kinases (RTKs)

Cell-surface receptors that are associated with many types of cancers.

HER2

A receptor tyrosine kinase that is often overexpressed in breast cancer cells.

Herceptin

A protein that binds to HER2 and inhibits cell division, used as a treatment for breast cancer.

Intracellular receptors

Proteins found in the cytoplasm or nucleus of target cells that bind to signaling molecules that have crossed the cell membrane.

Ligand-gated ion channel

A type of membrane channel receptor that opens or closes in response to the binding of a signaling molecule, allowing or blocking the flow of specific ions.

Neurotransmitter

A signaling molecule released at synapses between nerve cells that binds to ligand-gated ion channels, triggering the flow of ions and an electrical signal.

Voltage-gated ion channel

A type of ion channel that opens or closes in response to changes in electrical signals, crucial for the functioning of the nervous system.

Cell Communication

The process by which cells communicate with each other through the exchange of signals.

Aldosterone

A hormone that regulates water and sodium flow in kidney cells, ultimately affecting blood volume.

Receptor Protein

A protein that binds to specific signaling molecules, such as hormones, and initiates a cellular response.

Transcription Factors

Proteins that control which genes are turned on and transcribed into mRNA in a particular cell at a particular time.

Intracellular Receptors

Receptors located inside the cell, such as the aldosterone receptor, that function as transcription factors to turn on specific genes.

Signal Transduction Pathway

The chain of molecular interactions that leads to a cellular response after a signaling molecule binds to a receptor.

mRNA

Messenger RNA, a molecule that carries the genetic information from DNA to the ribosomes for protein synthesis.

Protein Kinases

Enzymes that add phosphate groups to proteins, often as part of a phosphorylation cascade in signal transduction pathways.

Phosphorylation Cascade

A series of protein phosphorylations in a pathway, where each protein adds a phosphate group to the next one, resulting in activation or inactivation of proteins.

Protein Phosphatases

Enzymes that remove phosphate groups from proteins, leading to their inactivation.

Protein Activation

The process of changing the shape or activity of a protein through phosphorylation or other modifications.

Protein Kinase 2

A specific protein kinase in a phosphorylation cascade that phosphorylates another protein, leading to the cell's response to the signal.

Cyclic AMP

A second messenger that transmits signals from the plasma membrane to the cytoplasm in response to an extracellular signal.

Adenylyl cyclase

An enzyme embedded in the plasma membrane that converts ATP to cyclic AMP in response to an extracellular signal.

G protein-coupled receptor

A receptor that, when bound by an extracellular signal such as epinephrine, activates adenylyl cyclase.

Phosphodiesterase

An enzyme that converts cyclic AMP to AMP, inactivating the second messenger.

Protein kinase A

A serine/threonine kinase that is activated by elevated levels of cyclic AMP and phosphorylates various other proteins.

Protein phosphatases

Enzymes that remove phosphate groups from proteins, inactivating protein kinases and turning off signal transduction pathways.

Second messengers

Small, non-protein, water-soluble molecules or ions that participate in signal transduction pathways. Examples include cyclic AMP and calcium ions.

Calcium ions (Ca2+)

One of the most widely used second messengers, involved in pathways initiated by both G protein-coupled receptors and receptor tyrosine kinases.

G protein systems

Regulatory systems that inhibit adenylyl cyclase in cell metabolism.

Adenylyl cyclase

An enzyme involved in cell metabolism that is blocked by inhibitory G proteins.

Cholera

A disease caused by the bacterium Vibrio cholerae, which produces a toxin that modifies a G protein involved in regulating salt and water secretion.

Cholera toxin

An enzyme produced by the cholera bacterium that chemically modifies a G protein, leading to continuous stimulation of adenylyl cyclase and high levels of cAMP.

cAMP

Cyclic adenosine monophosphate, a second messenger that is activated by cholera toxin and causes intestinal cells to secrete large amounts of salts into the intestines.

Cyclic GMP (cGMP)

A molecule similar to cAMP that is produced by muscle cells in response to nitric oxide and acts as a second messenger to cause muscle relaxation.

Nitric oxide (NO)

A gas released by neighboring cells that triggers the production of cGMP in muscle cells.

Viagra

A compound that inhibits the hydrolysis of cGMP to GMP, prolonging the signal and causing relaxation of blood vessels. It is used as a treatment for erectile dysfunction.

Calcium ions (Ca2+)

Signaling molecules that function as second messengers in animal cells, causing various responses such as muscle cell contraction and cell division.

Signal transduction pathways

Pathways that increase the cytosolic concentration of calcium ions in response to signaling molecules, such as neurotransmitters and hormones.