PRINCIPLES OF SIGNAL TRANSDUCTIONA Flashcards
These molecules and proteins are key components for successful cell communication.
- signaling molecules or the ligands
- receptors
- second messenger
Most cells in multicellular organisms, both emit and receive signals.
Receptors
Cell communication or signal transduction is mediated mainly by extracellular signal molecules (ligands)
Signaling molecules or ligands
TRUE OR FALSE
The reception of the signal depends on receptor proteins, always at the cell surface, which binds the signal molecule.
False (usually, but not always)
These targets are generally effector proteins, which are altered when the signaling pathway is activated and implements the signaling pathway is activated and implements the appropriate change of cell behavior.
Receptors
What are the 5 modes of cell signaling?
- Intacrine signaling
- Autocrine signaling
- Juxtacrine signaling
- Paracrine signaling
- Endocrine signaling
Needs a cell to cell interactions
- signals are produced for adjacent cells
Paracrine signaling
Takes place when the signal is directed to the same cell.
-This signal binds with a cell surface receptor, not a nuclear receptor.
Autocrine Signaling
Happens when a signaling molecule or a ligand is acting inside a cell.
Intacrine signaling
Is also known as contact-dependent signaling.
- The proximity between cells is mandatory for signaling to take place.
Juxtacrine signaling
Uses hormones as signaling molecules.
- This is for signals that need to travel over long distance.
Endocrine signaling
What are the types of cell-to-cell interactions?
- tight junctions
- anchoring junctions
- communicating junctions
In this type of interaction, direct physical contact is established that allows small molecules to pass.
Communication junctions
Are also called occluding junctions.
- They connect the plasma membranes of adjacent cells and prevent leakage of small molecules from between them.
Tight junctions
Are mechanically attached to the cytoskeleton of cell.
-They are usually found in the cells that make up the muscles and skins epithelium and can withstand some mechanical stress.
Anchoring junctions