Lecture - Protein sorting_ the Golgi apparatus.pptx (1)

What is the secretory pathway in protein sorting?

1. Translates from mRNA in the ribosomes in the cytoplasm 2. Enters the ER lumen 3. Goes from the ER to the Golgi in a vesicle 4. Transits the Golgi 5. Leaves the Golgi in a vesicle 6. The vesicle fuses with the cell membrane 7. It is outside.

What are the main functions of the Golgi apparatus?

Molecules are sorted at the Golgi, sugars serve as main destination tags, and there are two models of anterograde movement and retrograde movement.

What types of coated vesicles are there in transport?

The four well-characterized types of coated vesicles are clathrin-coated, COPI-coated, COPII-coated, and retromer-coated.

What do Rab proteins do in vesicle transport?

Rab proteins guide transport vesicles to their target membrane by displaying surface markers that identify them, while target membranes display complementary receptors.

What are the two mechanisms of transport through the Golgi apparatus?

1. Vesicles transport molecules between cisternae 2. Cisternae maturate from cis to trans along with cargo molecules.

What is the role of SNARE proteins?

SNARE proteins mediate membrane fusion by bringing the membranes into close proximity.

What is the KDEL sequence and its significance?

KDEL is a sequence (Lysine - Aspartic acid - Glutamic acid - Leucine) that initiates vesicle formation for ER proteins.

What happens to protocollagen during its transport through the Golgi?

Protocollagen assembly happens at the ER, it moves through the Golgi, and after secretion, it is trimmed by peptidase and assembles into a giant fiber.

How do cargo receptors function in vesicles?

Cargo receptors inside vesicles ensure they are loaded; activated receptors recruit adaptor proteins that recruit the coat proteins.

What is the difference between the secretory and endocytic pathways?

The secretory pathway leads outward from the endoplasmic reticulum (ER) toward the Golgi apparatus and cell surface, while the endocytic pathway leads inward from the plasma membrane.