Question

Please explain or diagram how specific molecules can be sorted out from a large EMS chamber (e.g., the Golgi or ER) and packaged in a vesicle.


Answer 1

Please explain or diagram how specific molecules can be sorted out from a large EMS chamber (e.g., the Golgi or ER) and packaged in a vesicle.

Ribosomes are proteinfactory of the cell which synthesize membrane bound and soluble proteins which gets attached to endoplasmic reticulum and further directed to different organelle destinations including the ER itself, the Golgi complex, endosomes, and lysosomes. The proteins are destined by the 'tag' that will convey specific target location and some tags are one or more phosphate groups attached to positions 3, 4, and/or 5 of a phosphatidyl-inositol molecule in the membrane. The major function of ER and early compartments of the Golgi stack is to retrieve or retain compartment-specific proteins from where the sorting begins. The above step is crucial to maintain the integrity of glycosylation and processing pathways.In trans-golgi network, the final sorting occurs when the lipids and proteins are selectively packaged into transport vesicles and destined to target organelle. Golgi complex play major role in protein process by endocytosis.

The vesicular trafficking is achieved by three major vesicular frameworks:

• COPII-coated vesicles - transport cargo proteins from the ER to the Golgi
• COPI-coated vesicles - transport cargo in the retrograde direction and between Golgi cisternae
• Clathrin-coated vesicles form - from the plasma membrane to fuse with endosomes or lysosomes

The major function of vesicle coats includes the deformation of membrane and populating with specific cargo by which the efficient protein sorting is achieved. The packed proteins inside COPII-coated vesicles fuses to form vesicular clusters which further combines to form the cis-Golgi network.