Final answer:
In endocytosis, adaptor proteins, clathrin, dynamin, actin, Hsc-70, and auxilin are involved in various stages such as vesicle formation, pinch-off, and uncoating. Ca2+ is crucial for triggering exocytosis, not endocytosis.
Step-by-step explanation:
The components involved in endocytosis each play unique roles in the process of internalizing substances into a cell:
- Adaptor proteins - They connect clathrin to the receptors on the cell membrane and help in cargo selection.
- Clathrin triskelia - Clathrin is the principal protein forming the structure of coated pits and vesicles in the cell membrane during endocytosis.
- Dynamin ring - Dynamin assists in the 'pinch-off' of the vesicle from the plasma membrane through GTP hydrolysis.
- Actin - It may be involved in providing mechanical force during the formation of vesicles.
- Hsc-70 - It's involved in the uncoating of clathrin-coated vesicles after endocytosis.
- Auxilin - It recruits Hsc-70 to clathrin vesicles to assist in uncoating.
Out of these components, Ca2+ is key in the initiation of neurotransmitter release during exocytosis, not endocytosis. It triggers the vesicles to fuse with the plasma membrane and release their contents out of the cell.