Exocytosis Overview

Flashcards covering key terms and concepts related to the process of exocytosis and its molecular mechanisms.

Exocytosis

The process of discharging a secretory vesicle or granule after fusion with the plasma membrane.

Secretory Vesicle

A membrane-bound structure that transports and releases substances outside the cell.

Plasma Membrane (PM)

The membrane that surrounds the cell and regulates the entry and exit of substances.

Calcium Ion (Ca2+)

An ion that triggers the process of exocytosis by increasing intracellular concentration.

Fusion Pore

The opening that forms between the vesicle and plasma membrane during exocytosis.

Luminal Part

The part of the vesicle membrane that becomes the outer surface of the plasma membrane.

Cytosolic Part

The part of the vesicle membrane that becomes the inner surface of the plasma membrane.

Endoplasmic Reticulum (ER)

An organelle involved in the synthesis and processing of secretory proteins.

Golgi Apparatus

An organelle responsible for modifying, sorting, and packaging proteins for secretion.

Antibodies

Proteins produced by plasma cells that help to identify and neutralize foreign objects.

Collagens

Proteins produced by fibroblasts that provide structural support to tissues.

Neurotransmitters

Chemical messengers released by neurons to communicate with other cells.

Perforin

A protein produced by T-cells that forms pores in target cell membranes.

Granzyme

A serine protease released by cytotoxic T-lymphocytes to induce apoptosis in target cells.

Clotting Factors

Proteins that help control blood clotting in response to injury.

Histamine

A chemical released by basophils that plays a role in immune responses and inflammation.

Insulin

A hormone produced by β-cells in the pancreas that regulates glucose levels in the blood.

Molecular Mechanism of Regulated Secretion

Involves a complex system of proteins and interactions that control secretion in response to signals.

Rab Proteins

GTP-binding proteins that regulate vesicular trafficking.

SNARE Proteins

Proteins that mediate the fusion of vesicles with target membranes.

Calmodulin

A calcium-binding messenger protein involved in various cellular processes.

Constitutive Secretion

The continuous, unregulated release of substances from cells.

Regulated Secretion

The release of substances that requires a specific trigger or signal.

Secretory Granules (SGs)

Larger storage vesicles containing secretory products for regulated secretion.

Proteolytic Processing

The breakdown of proteins into smaller polypeptides or amino acids.

Synaptic Vesicles

Vesicles that store neurotransmitters at presynaptic terminals.

v-SNARE

A type of SNARE protein located on vesicles involved in exocytosis.

t-SNARE

A type of SNARE protein located on target membranes.

Presynaptic Membrane

The membrane at the end of a nerve cell that releases neurotransmitters.

Neurotransmitter Release

The process by which neurotransmitters are expelled from synaptic vesicles into the synaptic cleft.

Action Potential

An electrical signal that triggers neurotransmitter release at nerve terminals.

Endocytosis

The process by which cells internalize substances from their environment.

Neurotransmitter Transporter Proteins

Proteins that facilitate the loading of neurotransmitters into synaptic vesicles.

Endosome

An organelle that processes endocytosed material within a cell.

Synapsin

A protein that regulates the availability of synaptic vesicles for release.

Complexin

A protein that stabilizes SNARE complexes and regulates neurotransmitter release.

Calcium Binding Sites

Specific regions on proteins that interact with calcium ions, facilitating exocytosis.

Membrane Size Regulation

The process that maintains the size and composition of the plasma membrane.

Rapid Exocytosis

A quick release of neurotransmitters, often occurring in response to stimuli.

Priming

The process of preparing synaptic vesicles for fusion with the presynaptic membrane.

Fusion Complete

The final stage of vesicle fusion when contents are released into the extracellular space.

Docking

The initial attachment of a vesicle to a target membrane prior to fusion.

Molecular Biology of the Cell

A major textbook in cellular biology that covers various aspects including secretion.

Cytoplasm

The gel-like substance within a cell where cellular processes occur.

T-cells

A type of immune cell that plays a central role in cell-mediated immunity.

Synaptotagmin

A calcium sensor in synaptic vesicles that triggers exocytosis upon calcium binding.

Rho/Rac/Cdc42

GTPases involved in regulating cytoskeletal dynamics during exocytosis.