1. Cell-Cell Communication, Sensing and Chemotaxis
N Kuldell for
Spring 2009

2. Heidelburg iGEM 2008: ecolicense to kill
Part 1: Sensing
Background information

3. Cell-Cell Communication natural context: Cuttlefish and Vibrio harveyi
Cuttlefish: master of camouflage
During the day they lie buried in the bottom of the ocean; at night they swim and hunt for food.

4. Cell-Cell Communication natural context: Cuttlefish and Vibrio harveyi
AI-2
AI-1
Few cells: Autoinducers diffuse away
More cells: Autoinducers initiate signaling, transcription
Photo from B. Bassler, Fig from:
Genes & Dev :
doi: /gad

5. Cell-Cell Communication
iGEM context: “prey” pathogen, “predator” killer
Prey Cell
LuxS= enzyme that produces autoinducer 2 (AI2)…diffuses through the media
Predator Cell
Nature (2002) 415: 545
LuxP, LuxQ = receptor that binds (AI2)…induces chemotaxis….how?

6. Sensing and Signaling Cascades
natural context: “TCS” 2 component signaling
AI-2
AI-1
Stimulus
Activates SHK
Transfers to RR
Output P
TCS
“SHK” sensor histidine kinase
“RR” response regulator

7. Sensing and Signaling Cascades
natural context: “TCS” 2 component signaling
Stimulus
Activates SHK
Transfers to RR
Output P
TCS
“SHK” sensor kinase
“RR” response regulator
Plant Physiol. (1998) 117: 723

8. Sensing and Signaling Cascades
natural context: “TCS” 2 component signaling
Stimulus
Activates SHK
Transfers to RR
Output
Tar
Che
flagella P
CCW, default, tumble
CW, signal, swim
TCS
“SHK” sensor kinase
“RR” response regulator
J Bacteriol. (2000)182: 6865

9. Sensing and Signaling Cascades iGEM context: chimeric receptor