Lecture Notes

Lecture 22

Cell communication to maintain or establish cell polarity

 Cell polarity can be either basal/ apical or rear to front
 Cells communicate with the cellular environment:
- growth factor
- growth factor receptors
- ECM
- Integrins
 Cells communicate with the surrounding cells:
- cell-cell junctions (cadherins)
cadherin is not a receptor for a substrate
Cadherin undergoes homophillic binding (= 1 cadherin binds to another in the neighbour cell)
 these communications all influence the ‘’inside’’ of the cell:
- signalling pathways (switched on)
- Change in cytoskeleton (actin, microtubules, IF)
 and leads to cell responses:
- maintain apical-basal polarity
- migration




Growth factor and growth factor receptors

 GF trigger different cell responses
- Proliferation
- Survival
- Migration
 Immediate response
- Do not require gene transcription
 Delayed response
- Require gene transcription

, Receptor tyrosine kinase (RTK)

 GF bind to respective GF receptor
 Most GF receptors are RTK but not all
- RTK is a GF receptor but a GF receptor is not always an RTK
 There is an RTK family and all have a kinase domain (in red)
- The kinase domain is enzymatic and phosphorylates some docking sites downstream the kinase domain on the
receptor
 paracrine signalling
 proto-oncogene