Hydrophilic signals and transduction Flashcards
Where do
Hydrophilic signalling molecules bind
To transmembrane receptors and do not enter the cytosol
Examples of
Hydrophilic extracellular signalling molecules
Peptide hormones and neurotransmitters
Hydrophilic signalling pathway
Ligand binds to extracellular face, transmembrane protein changes conformation, signal molecule does not enter the cell but the signal is transduced accross the plasma membrane
Transmembrane receptors act as
Signal transducers by converting the extracellular ligand binding event into intracellular signals, which alters behaviour of the cell
Transduced hydrophilic signals involve
G proteins
or
Cascades of phosphorylation by kinase enzymes
What do
G proteins do ?
Relay signals from activated receptors to target proteins
Phosphorylation cascades
Involve and allow
- More than one intracellular signalling pathway is activated
- Involve a series of events with one kinase activating the next in the sequence
What can
Phosphorylation cascades result in
In the phosphorylation of many proteins because of the original signalling event
Binding of insulin
-Insulin binds to its receptor, causing it to undergo a conformationl change
-This Triggers phosphorylation of the receptor
- Which starts a phosphorylation cascade inside the cell
- Leading to vesicles containing GLUT4 transported into cell membrane
Where do
GLUT4 glucose transporters go
after insulin binds to its receptor
To the cell membrane of fat and muscle cells
Diabetes mellitus caused by
Failure to produce insulin, or loss of receptor function
Apart from binding of insulin, what else triggers recruitment of
GLUT4
Exercise, so uptake of glucose to fat and muscle cells improves in type 2
