Case 2 - BBS2042

This set of flashcards covers key vocabulary and concepts related to cell-derived signaling molecules, including their types, functions, mechanisms, and roles in cellular communication.

Signaling molecules

Substances released by cells that bind to specific receptors on target cells to trigger a biological response.

Types of signaling molecules

Peptides, purines, pyrimidines, proteins, lipids, and gases.

Neurotransmitters

Chemical signals in the nervous system, can be either excitatory or inhibitory.

Peptides

Short chains of amino acids that act as signaling molecules.

Proteins

Longer, folded chains of amino acids that function as signaling molecules.

Examples of peptides

Insulin, glucagon, vasopressin, and oxytocin.

Examples of proteins

Growth hormone, cytokines (IL-2, TNF-α), and erythropoietin.

Neuropeptides

Large peptides that include substance P and endorphins.

Hydrophilic signaling molecules

Cannot cross lipid bilayers and bind to cell-surface receptors.

Signaling molecule transport

Involves binding to cell-surface receptors like GPCRs and ionotropic receptors.

Endocrine signaling

Signaling mediated by hormones released into the bloodstream.

Paracrine signaling

Local signaling where molecules affect nearby cells.

Autocrine signaling

Signaling where cells respond to signaling molecules they secrete.

Purines

Nucleotide-based signaling molecules such as ATP, ADP, and adenosine.

Pyrimidines

Nucleotide-based signaling molecules including UTP and UDP.

P1 receptors

Class of receptors that bind adenosine, often inhibitory or modulatory.

P2 receptors

Receptors for nucleotides; P2X are ligand-gated ion channels, P2Y are GPCRs.

Eicosanoids

Signaling molecules derived from arachidonic acid, including prostaglandins.

Steroid signaling molecules

Hydrophobic molecules like cortisol and estrogen that act via intracellular receptors.

Endocannabinoids

Signaling molecules like anandamide that bind to CB1 and CB2 receptors.

Gaseous signaling molecules

Small, diffusible gases like NO, CO, and H2S that act locally.

Neurotransmitter criteria

1. Synthesized in the neuron, 2. Stored in synaptic vesicles, 3. Released upon depolarization, 4. Binds receptors, 5. Terminated by reuptake or degradation.

Glutamate

Excitatory neurotransmitter, essential for learning, memory, and synaptic transmission.

GABA

Inhibitory neurotransmitter synthesized from glutamate.

Glycine

Major inhibitory neurotransmitter in the spinal cord and brainstem.

Vesicles

Membrane-bound compartments that transport cargo within cells.

COPII vesicles

Transport newly synthesized proteins from the rough ER to the Golgi apparatus.

COPI vesicles

Primarily involved in the retrograde transport of proteins from the Golgi to the ER.

Secretory vesicles

Transport signaling molecules like hormones and neuropeptides and release them upon stimulus.

Multivesicular bodies (MVBs)

Endosomes containing intraluminal vesicles that can either degrade or secrete cargo.

Exosomes

Small extracellular vesicles released from MVBs that facilitate intercellular communication.

Microvesicles

Larger extracellular vesicles formed by direct outward budding of the plasma membrane.

Gene transcription

Process by which a gene's DNA sequence is transcribed to produce mRNA.

Translation

Ribosomes synthesize proteins based on the mRNA sequence.

Protein folding

The process where proteins fold into their functional 3D shapes.

Calcium-dependent exocytosis

Release of signaling proteins triggered by calcium influx.

SNARE proteins

Mediators of membrane fusion during exocytosis.

Vesicle docking

Process where vesicles bind to target cell membranes before fusion.

Endocytosis

The process by which cells take in materials by engulfing them in membrane-bound vesicles.

Signal termination

Decoupling of signal transduction pathways to end the signaling response.

Release of extracellular vesicles

MVBs fuse with the plasma membrane to release exosomes and microvesicles.

Target cell binding

Specific interactions between vesicular ligands and receptors on target cells.

Surface signaling

Signaling that occurs when the EV membrane proteins act as ligands.

Endosomal signaling

Signaling that occurs within endosomes after EV uptake.

Cytosolic cargo action

Functional effects of components within the cytosol following EV fusion.

Gaseous signaling properties

Small gases that diffuse across membranes and act locally.

Nitric oxide (NO)

A gas signaling molecule produced by nitric oxide synthase (NOS) in response to calcium.

Nitric oxide functions

Vasodilation, modulation of synaptic plasticity, cytotoxicity to pathogens.

Carbon monoxide (CO)

A gas produced by heme oxygenase, involved in neuromodulation and cytoprotection.

Hydrogen sulfide (H₂S)

A gas involved in vasodilation and synaptic modulation, produced in tissues.

Comparison of gasotransmitters

Comparison based on features like production, diffusion, and speed.

Vesicle maturation

Process whereby vesicles develop from immature to mature states, including cargo concentration.

Constitutive secretion

Continuous release of proteins without external signaling.

Regulated secretion

Release of proteins that requires specific stimuli.

Extracellular signal involvement

External signals can trigger exocytosis via calcium influx.

Exosome functions

Intercellular communication, immune modulation, and acting as biomarkers.

Evoked neurotransmitter response

Rapid neurotransmitter release due to depolarization or stimulus.

Distinctive vesicle roles

Specific functions attributed to different types of vesicles in cellular processes.

Lipid bilayer protection

EVs protect their cargo from degradation in extracellular environments.

Specificity in EV targeting

Highly selective binding between receptor-ligand pairs on target cells.

Functional cargo transfer

The horizontal transfer of active molecules such as proteins and RNA between cells.

Intercellular communication

Mechanisms by which cells signal to and receive signals from neighboring cells.

Short half-life of signaling molecules

Fast degradation and inactivation alone facilitate rapid cellular responses.

Formation of signaling niches

Binding of EVs to ECM components, creating local environments conducive to specific signaling.

Eicosanoids' role

Signaling molecules involved in inflammation and pain regulation.

Calmodulin interaction

A mediator in calcium signaling pathways contributing to muscle relaxation.

Synthesis of gaseous signaling molecules

Produced rapidly in response to cellular stimuli affecting nearby cells.

Gaseous signaling logic

Sequential steps depicting how gases are produced and act within tissues.

Local signaling characteristics

Features of gaseous mediators acting primarily within small distances.

Signaling characteristics of peptides and proteins

Fast onset and short-lived effects amplified via second messengers.