Signalling Flashcards
What can signalling influence cells to do?
Cell survival and division
Cell differentiation
Programmed cell death
What are the types of cell signalling?
Direct cell signalling
Indirect cell signalling
What are the types of indirect cell signalling?
Autocrine
Paracrine
Endocrine
What is autocrine signalling
.
Cells signalling to themselves
What is paracrine signalling?
Cells signal to other nearby cells
What is endocrine signalling?
Cells signal through the blood stream to others that are further away
What are gap junctions?
Channels that directly connect adjacent cells
Which molecules can pass through gap junctions?
Only small molecules - anything smaller than 1KDa
What are connexins?
The proteins forming gap junctions
How is a gap junction formed?
When two cells in contact align, connexons pair to form a channel.
A gap junction forms when many channels are present
How many connexin genes are there in the human genome?
21
What causes gap junction selectivity?
Differences between the amino acids that face the internal channel
What causes negative feedback in autocrine signalling?
The cell secretes a ligand that when bound to the receptor causes the cell to stop producing any more ligand
What causes positive feed forward in autocrine signalling
The cell secretes a ligand that when bound to the receptor causes the cell to increase ligand production
