1.4.3 hydrophilic signals and transduction Flashcards
do hydrophilic signalling molecules enter the cytosol
no
what do hydrophilic signalling molecules bind to
transmembrane receptors
what are examples of hydrophilic extracellular signalling molecules
peptide hormones and neurotransmitters
when do transmembrane receptors change conformation
when the ligand binds to the extracellular face
do signal molecules enter the cell
no
what is the signal transduced across
the plasma membrane
what do transmembrane receptors act as
signal transducers
how do transmembrane receptors act as signal transducers
they convert the extracellular ligand binding event into intracellular signals
how do transmembrane receptors alter the behaviour of the cell
by converting the ligand binding event into intracellular signals
what do transduced hydrophilic signals often involve
G-proteins or cascades of phosphorylation kinase enzymes
what do G-proteins do
they relay signals from activated receptors to target proteins such as enzymes and ion channels
what are activated receptors
receptors that have bound to a signalling molecule
what do phosphorylation cascades allow
they allow more than one intracellular signalling pathways to be activated
what do phosphorylation cascades involve
a series of events with one kinase activating the next in the sequence and so on
what can phosphorylation cascades result in
the phosphorylation of many proteins as a result of the original signalling event
what does the binding of the peptide hormone insulin to its receptor result in
an intracellular signalling cascade that triggers recruitment of GLUT4 glucose transporter proteins to the cell membrane of fat and muscle cells
what does the binding of insulin to its receptord do that triggers phosphorylation of the receptor
it causes a conformational change
what does the phosphorylation of the insulin receptor start
a phosphorylation cascade inside the cell, which eventually leads to GLUT4-containing vesicles being transported to the cell membrane
how can diabetes mellitus be caused
failure to produce insulinm or loss of receptor function
how can recruitement of GLUT4 be triggered
exercise
