test 2, 14 vesicular trafficking Flashcards
What is the best environment for lysosomes?
- acidic with proteolytic cleavage sites
What are lysosomes best used for?
intracellular digestion
What maintains the acidic environment that lysosomes require to operate?
Vacuolar ATPase. Pumps H ions into the lysosomes environment
What are the different stages of lysosome development?
- early endosom
- late endosome
- endolysosome
- lysosome
What methods allow compounds to enter into a lysosome?
- phagocytosis
- endocytosis
- autophagy
- macropinocytosis
What sorts hydrolases to lysosome form the TGN?
- mannose-6-phosphate is required.
2. helps form a clathrin coated vesicle that is delivered to endosome and develops into lysosome
What compound is used to add the M6P to the lysosomal hydrolase?
UDP-GlcNAc, which ultimately will fall off and leave M6P attached
What is Hurler’s disease?
- mutation occurs in the enzyme that degrades glycosaminoglycan chain
What is inclusion cell disease?
- lysosomal hydrolases are absent in multiple cell types, leading do substrate accumulation
What enzyme is responsible for attaching M6P to lysosomal hydrolases?
- GlcNAc phosphotransferases. no phosphorylation means no signal that delivers vesicles to the lysosome.
If GlcNAc is mutated and ineffective, where will compounds be transported if not sent to the lysosome?
- cell surface and secreted into the bloodstream
What is endocytosis?
invagination of the PM that forms an endocytic vesicle of components from outside the cell. Use phagocytosis or pinocytosis
What is receptor-mediated endocytosis?
- selective concentration mechanism of uptake.
2. utilizesmolecules that bind to receptors and accumulate in clathrin-coated pits
What is one example that utilizes receptor-mediated endocytosos? What happens if something in the system were to fail?
- cholesterol
2. atherosclerosis
What are the fates of proteins that have been endocytosed?
- degradation via endolysome
- transcytosis out of the cell
- recycle of transport vesicles