E8 Flashcards
Glucocorticoid receptors
Gene specific transcription factors that are released from the cytoplasm upon hormone binding
How does a peptide hormone cause a change in transcription the nucleus
It binds to a receptor on the outside of the cell membrane and this causes changes on the inside of the cell
Gy
What is phosphorylation
The addition of a phosphate group po4 3-
Usually catalyzed by enzymes called kinases
How does phosphorylation work
Addition of a phosphate group often induces a conformational change in the target protein which can activate or inhibit the protein function
Dephosphorylation / inactivation or switching off
Removal of phosphate group from a protein
Removal of phosphate group reverse the conformational change, returning the protein to it’s in active state
Signal transduction cascade
It amplifies signal and carries it into the cell
Steps
The receptor kinase is activated by the allosteric switch
Intracellular kinase activated by phosphorylation
Phosphorylation of target proteins
Where could a cancer drug act to block or reduce receptor activation
Use an antagonist: a molecule that prevents activation of receptor
Use a kinase innibior: a molecule that prevents the enzymatic activity of the receptor or downstream kinases
Regulation of transcription
Main control mechanism of gene expression
Regulates the amount of pre-mrna synthesised
Splicing
Determines which parts of the pre- mRNA end Up in the mRNA
Regulation of translation
Determines how much protein is made from a particular mRNA and therefore the protein level
Regulation of mRNA degradation
Determines how fast an mRNA is degraded and therefore the level of an mRNA
Regulation of protein degradation
Determines now fast a protein is degraded and therefore protein level
Splicing
Removes introns from the pre-
Exons are expressed
