L13 - Intracellular Transport 2

UNT Bio 3510

Vesicular transport

The movement of materials within a cell via membrane-bound vesicles.

Vesicle

" A small, membrane-enclosed sac that stores and transports substances within a cell."

Secretory pathway

The route by which proteins and lipids are transported from the ER to the Golgi and then to the cell surface or lysosomes.

Endocytic pathway

The route by which materials are internalized into the cell through membrane invagination and vesicle formation.

Vesicle budding

" The process by which a vesicle pinches off from a membrane, forming a separate compartment."

Clathrin-coated vesicle " A vesicle surrounded by a coat of clathrin proteins, involved in endocytosis and transport from the Golgi."

Clathrin

" A protein that forms a cage-like structure around vesicles, facilitating their budding."

Dynamin

A GTPase protein that pinches off clathrin-coated vesicles from the membrane.

Cargo receptors

Membrane proteins that bind to specific cargo molecules and concentrate them in vesicles.

Adaptins

" Proteins that link cargo receptors to clathrin, facilitating vesicle formation."

COP-coated vesicle

" A vesicle coated with coat proteins (type I or II), involved in transport between the ER and Golgi."

Tethering

" The initial attachment of a vesicle to its target membrane, mediated by tethering proteins."

Docking

" The precise alignment of a vesicle with its target membrane, involving SNARE proteins."

Fusion

" The merging of a vesicle membrane with its target membrane, releasing the vesicle's contents."

Rab

A family of small GTPase proteins that regulate vesicle trafficking and targeting.

V-snare

A vesicle-associated SNARE protein that interacts with t-SNAREs to mediate membrane fusion.

T-snare

A target membrane-associated SNARE protein that interacts with v- SNAREs to mediate membrane fusion.

Exocytosis

" The process by which vesicles fuse with the plasma membrane, releasing their contents outside the cell."

Endocytosis

The process by which the cell internalizes materials by forming vesicles from the plasma membrane.

Constitutive secretion

" The continuous release of proteins and lipids from the cell, without a specific signal."

Regulated secretion

The release of proteins and lipids (and other molecules) from the cell in response to a specific signal.

Secretory vesicles

Vesicles that store and release proteins and lipids via exocytosis.

Phagocytosis

" The engulfment of large particles or cells by a cell, forming a large vesicle called a phagosome."

Pinocytosis

" The uptake of fluids and small molecules by a cell, forming small vesicles."

Receptor-mediated endocytosis

" The selective uptake of specific molecules by a cell, involving receptor proteins on the cell surface."

Endosome

" A membrane-bound compartment that receives vesicles from the plasma membrane, sorting and directing their contents."

Lysosome

A membrane-bound organelle containing hydrolytic enzymes that degrade macromolecules and cellular debris.

Autophagy

The process by which a cell degrades its own damaged organelles or proteins within lysosomes.

ER

" Endoplasmic reticulum, a network of membranes involved in protein and lipid synthesis."

Disulfide bond

" A covalent bond formed between two cysteine residues, stabilizing protein structure."

Glycosylation

" The addition of carbohydrate groups to proteins, often occurring in the ER and Golgi."

Unfolded protein response

A cellular stress response triggered by the accumulation of misfolded proteins in the ER.

Protein chaperones

" Proteins that assist in the proper folding of other proteins, preventing aggregation."

Golgi

" A membrane-bound organelle that modifies, sorts, and packages proteins and lipids for transport to their final destinations."