Lecture 7: Cell-Cell Communication

Question 1

Name 2 kinds of cell-cell signalling

Answer 1

1. Contact dependent

2. Secreted molecules

Question 2

Name 7 Juxtacrine Signalling

Answer 2

1. Gap-junctions
2. Plasmodesmata
3. Notch
4. Autocrine signalling
5. Paracrine signalling
6. Paracrine signalling (synaptic)
7. Endocrine signalling

Question 3

Describe Gap junctions, plasodesmata and notch

Answer 3

GJ- Caridomyoctye
- Action potential in pacemaker cells, then GJ allows cations (Ca2+ and Na+) to pass freely between linked cells - allowing syncytium

Plasmodesmata
- Creates gaps that connect plant cells
ER extension- desmotubule, cytoplasmic sleeve (around tubule)
Transports metabolites, proteins, RNA

Notch
- In neuronal development, glial support of neurons and in learning & memory

Question 4

Describe Autocrine signalling

Answer 4

Release of molecules by a cell that only act on the cell itself

Question 5

Paracrine Signalling

Answer 5

Cell secretes molecules and can act on multiple cell pop. that are local to secreting cell

Question 6

Paracrine signalling (synaptic)

Answer 6

Neuron releases molecules, bind to receptor structure that is close by

Question 7

Endocrine signalling

Answer 7

Molecule released into bloodstream, can travel far in body before finds target cells

Question 8

Describe Paracrine

Answer 8

Cytokines release by immune cells act on multi pop
Morphogens released to drive patterning during develop
Neurotransmitters released locally act on multi targets

Question 9

Define Morphogens

Answer 9

Secreted from particular location and form gradients within tissues
WNT proteins cells respond in concentration-dependent manner - establishing positional patterning

Question 10

WNT signalling pathway overview

Answer 10

1. WNT binds to frizzled receptor
2. in case of stimulation of canonical pathway - Beta-catenin is stabilised in cytoplasm
3. Transported to nucleus
4. Binds to transcription factor Tcf and turns on gene expression