Joint 7 - Cell Communication & Proliferation Flashcards
1
Q
what are tyrosine kinase receptors?
A
- enzyme coupled receptor
- receptors that dimerise when phosphorylated at the tyrosine residue
- have a kinase domain that gets transphorphorlayted
2
Q
how do tyrosine kinase receptors downstream a signal?
A
- signal mol binds
- receptors dimerise as tyrosine is transphosp at the kinase domain
- phosphates are now a docking site
- intracell sig proteins can bind
3
Q
steps of the RAS pathway?
A
- TY.KIN.RECEP activated and forms docking sites
- grb2 [adaprot protein] attaches
- grb2 activates SOS [rad activating protein]
- RAS is a GTPase and SOS causes it to become bound to GTP [activated]
4
Q
MAP kinase pathway?
A
- Ras is active [GTPbound]
- activate RAF [not by phos!]
- Raf activates Mek [by phos]
- Mek activates Erk [by phosp]
Erk can phos many other targets
5
Q
what does MAP kinase control?
A
- the cell cycle start
- occur during G1
6
Q
structure of phosphotidylinositol?
A
phospholipid with inoistiol molecule
7
Q
how is phosphatidylinositol converted to IP3 and DAG?
A
- the PI has the inositol phosphorylated by a kinase
- forms PIP2 [inoisitol phosphorylated]
- PIP2 broken to IP3 and DAG by enzyme called PLC
- IP3 is inositol with 3 phosp attached
- DAG is orginial phospholipid without the phosphate attached to glycerol
8
Q
how does IP3 cause Ca release?
A
- receptor bind to g-protein a-unit
- a-unit activates PLC
- form DAG and IP3
- IP3 binds to a receptor in ER - causes Ca release
9
Q
how are signal intergrator proteins regulated?
A
- phosphorylated or dephos
- they integrate multiple signals to form outsome
- combination of phosph’s at the Tyrosines and Serines and Threo determine response
10
Q
what is HER2?
relation with cancer?
A
- HER2 is a tyrosine kinase receptor
- in cancerous cells, they have more HER2
- Herceptin targets it by attaching antibody to one receptor [cause immune resp]
