Chapter 14 - Vesicular Traffic, Secretion, and Endocytosis

Vocabulary flashcards based on lecture notes about vesicular traffic, secretion, and endocytosis.

Secretory Pathway

Distribution of soluble and membrane proteins synthesized by the rough ER to final destinations at the cell surface or in lysosomes.

Endocytic Pathway

Vesicles budding from the plasma membrane take up soluble extracellular proteins and deliver them to lysosomes via late endosomes.

Transport Vesicles

Collect cargo proteins in membrane budding from a donor compartment and deliver cargo proteins to the next compartment by fusing with the target membrane.

Constitutive Secretion

Transport vesicles move continuously and fuse with the plasma membrane; occurs in all cells.

Regulated Secretion

Proteins accumulated and stored in regulated secretory vesicles; vesicles fuse with plasma membrane and secrete proteins only when cell receives a neuronal or hormonal signal; occurs in certain cell types.

COPII-coated vesicles

Transport newly synthesized proteins containing Golgi-targeting sequences in their cytosolic domain or bound to such proteins from the rough ER to the cis-Golgi (anterograde direction).

COPI-coated vesicles

Transport vesicles carrying ER/Golgi-resident proteins in the retrograde direction, which supports Golgi cisternal maturation.

KDEL receptor

Involved in retrieval of ER-resident luminal proteins from the Golgi.

trans-Golgi network

Sorts proteins into vesicles targeted for different destinations.

Clathrin-coated vesicles

Transport lysosomal enzymes to late endosomes for eventual delivery to lysosomes.

Dynamin

Required for pinching off of clathrin-coated vesicles; polymerizes around vesicle neck and hydrolyzes GTP.

Receptor-Mediated Endocytosis

Extracellular ligands bound to specific cell-surface receptors with cytoplasmic domain AP2-targeting sequences are internalized by clathrin-coated vesicles.

Autophagy

Envelopes a region of cytoplasm or an organelle into a double-membrane autophagosome for delivery to a lysosome.