Lecture 3-11: Secretory and Endocytic Pathways

SNARE proteins

Membrane-bound proteins that mediate fusion between vesicles and target membranes.

v-SNARE

SNARE proteins located on vesicles.

t-SNARE

SNARE proteins located on target membranes.

Rab protein

A G protein that facilitates vesicle docking by binding to tethering proteins on target membranes.

N-glycosylation

The addition of sugar molecules to asparagine residues on proteins.

Glycocalyx

A glycoprotein and glycolipid covering that surrounds the cell membranes, originating from the endoplasmic reticulum.

Chaperones

Proteins that assist in the proper folding of other proteins.

ER stress

A condition resulting from the accumulation of improperly folded proteins in the endoplasmic reticulum.

Phagocytosis

A type of endocytosis where large materials are engulfed by the cell.

Endocytosis

The uptake of extracellular materials into the cell.

Regulated secretion

Secretion of substances from cells that is controlled by specific signals, such as calcium influx.

Constitutive secretion

Continuous secretion of newly synthesized proteins without the need for specific signals.

Lysosomes

Organelles that contain digestive enzymes to break down macromolecules.

Autophagy

A cellular process that recycles organelles in starved cells.

Endosome

A membrane-bound compartment that materials enter after being endocytosed.

Transcytosis

The transport of materials from one side of a cell to the other side via vesicles.

Calnexin

A calcium-dependent chaperone assisting in the folding of proteins in the ER.

Tunicamycin

A compound that inhibits N-glycosylation, leading to protein retention in the ER.

Voltage-gated calcium channels

Channels that open in response to an action potential, allowing calcium influx.

Macromolecules

Large complex molecules, such as proteins and polysaccharides, that are digested in lysosomes.