Cell Biology Lecture 18: Intracellular Trafficking and Transport

What are signal sequences necessary for

focalization of organelles

What facillitates transport of cargo

nuclear pores

Where is cargo released? Recycled?

nucleus, cytoplasm

GAP 

promotes hydrolysis of GPT into GDP

GEF

promote exchange of GDP for GTP

Cytosol

High Ran GAP low ran GEF

nucleus

high Ran GEF low ran GAP

Constitutive Secretion

No stimulus or signal required for vessicle fusion with plasma membrane

Example of Constitutive Secretion

Collagen, Fibernectin, mucous

Regulated Secretion

Requires a stimulus in order for vesicle fusion with plasma membrane,

Example of regulated secretion

Insulin, specific inflammatory cyytatenes, neurotransmitters

Vesicle Formation Process

binding between cargo protein and transmembrane receptor following binding to the receptor, adaptin and Clathrin bind outer surface, Dynamin facilitate release of vessicle form the membrane. Following release clatrhin and adaptin dissociate

Vesicle Fusion Process

Rab bind to Tether snare bind and facilitate vessicle fusion with membrane 

Rab Protein

Specific to organelle of origin

Tethers

specific to destination organelle

V snare

Specific to origins

T snare

specific to target destination

Lyosome characteristics

digestion of macromolecules into monomers for recyclin, acidic leads to denaturation of protein due to disruption of ionic bonds, aciditiy mainted by proton ATPase pump, high protein concentration in lysosome.