Term
| Describe the process of constitutive uptake with a recycling receptor and give an example of it |
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Definition
1. Ligand binds to surface receptors
2. Invagination of surface receptor
3. Coating of vesicle (as it forms) with surface proteins
4. Transport of coated vesicle to endosome (becomes uncoated during this time)
5. Transport of ligand to lysosome for degradation and release of surface receptor into vesicle for transport back to surface
Example: LDL |
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Term
| What is the main role of the lysosome and how does it accomplish this? |
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Definition
- Degradation of cell components and internalized material
- Accomplishes this through having an acidic environment (pH=5) and possessing acid hydrolases to degrade components |
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Term
| Movement of vesicles from donor membranes to acceptor membranes are controlled by what? |
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Definition
| Motor proteins on cytoskeletal filaments |
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Term
| Direction of vesicles from donor membranes to acceptor membranes are controlled by what? |
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Definition
| Motor proteins on cytoskeletal filaments |
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Term
| What are the 3 types of coating proteins and where does each transport to/from? |
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Definition
1. Clathrin - Surface proteins to lysosomes
2. COP II Coatomer - ER to Golgi
3. COP I Coatomer - Golgi to ER |
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Term
| What surface proteins control specificity and direction of vesicles? |
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Definition
| SNARES (v-SNAREs on vesicles bind to t-SNAREs on targets) |
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Term
| Describe the process by which SNAREs come in close enough contact with each other to bind |
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Definition
| Phosphorylated Rab GTPases on the surface of the vesicles bind to Rab effector proteins on the surface on targets which bring the SNAREs close enough to bind, allowing the vesicle to fuse with the target (Process is called "tethering") |
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Term
| By what mechanism do proteins migrate toward specific organelles? |
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Definition
| Organelle-specific targeting sequences are attached to the proteins to direct them to specific locations |
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Term
| Name two organelles that use specific uptake-targeting sequences to attract proteins |
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Definition
1. Mitochondria
2. Peroxisome |
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