Intracellular Compartments & Transport

Nuclear Localization Signals (NLS)

Short stretches of amino acid sequences in proteins that direct them to the nucleus.

Importins

Specialized nuclear import receptors that recognize NLS and transport proteins to the nucleus.

Nuclear pore complexes (NPCs)

Structures that mediate the transport of molecules between the nucleus and cytoplasm.

Signal Recognition Particle (SRP)

A ribonucleoprotein complex that binds to the signal sequence emerging from the ribosome.

Translocon

A channel in the ER membrane where the ribosome-nascent chain complex docks for protein translocation.

COP-coated vesicles

Transport vesicles characterized by coat proteins that bud off from membranes.

Clathrin

A protein that forms the outer layer of clathrin-coated vesicles, involved in endocytosis and transport.

SNAREs

Transmembrane proteins that catalyze membrane fusion for vesicle transport.

Endocytosis

The process by which substances are imported into the cell, involving membrane engulfment.

Exocytosis

The process by which substances are exported from the cell through vesicle fusion with the plasma membrane.

Ribosomes

Cellular structures that synthesize proteins by translating messenger RNA.