L2b - steriod hormone action Flashcards
location of receptors for glucocorticoids, sex hormones inside the cell
cytoplasm
location of receptors for thyroid, vit D inside the cell
nucleus
how many gene encodes for steriod receptors
one
what else SHRs can function as
transcription factors
types of nuclear hormones receptors
type 1 and 2
what happens during type 1 complex
ligand or hormone binds to nuclear receptor bound to HSP in the cytosol.
- when the binding happens, the HSP complex is dissociated and results from cytoplasm to nucleus
- nuclear receptor with DNA complex - causes a change in a protein
what happens during type 2 complex
- HSP complex not present
- ligand directly binds to DNA as hetero dimers
- corepressor proteins get dissociated after being in a complez with the receptor
nuclear receptor proteins acts as ?
transcription factors
what does a hormone do to a gene expression
-changes the apttern
where do steriod receptors dimers bind to on the genes
in the promotor regions
how does a hormone alter the gene expression
- 1st - binds to the target sequ of the DNA through it receptor using zinc fingers
what are zinc fingers
a loop of peptides that has bound zinc ion at one end,
function of 1st zinc finger
binds to DNA
function of 2nd zinc finger
involved in dimerisation
what are HRE
hormone response elements
-DNA sequence for a hormone that acts by binding to a receptor that can act as a transcription factor,
