Systems biology of the cell Flashcards
What do cells need to do?
Divide (know when to stop), move to other places and stay put, differentiate into appropriate cell type, function physiologically and biophysically.
What do cells need to do everything that they need to do?
Need to communicate with one another, to stick to one another and become POLAR.
What did Steinberg (1963) propose as the differential adhesion hypothesis?
That cell sorting could be explained as driven by differential adhesion between cel types within a tissue.
What do cells that adhere more with one another form?
A tissue with higher surface tension.
What will tissues with different surface tensions do?
Separate.
How can surface tension of a cell aggregate be measured?
By squeezing it - differential adhesion driven cell sorting.
How can you test the hypothesis of differential adhesion?
Make an in silico cell - using the computer to model a cell.
What are cell surface mechanics considered as?
The basic ingredients of describing a simple cell.
What are in silico cells like?
Non-polar, membrane has small fluctuations that are non-directed.
What is the outcome of in silico cells?
Cells tend to round up alone but acquire honey-comb lattice shapes when in contact with other cells - as they adhere; they also form an aggregate.
Why do these parameters reflect molecularly?
Adhesions is mediated between cells through cadherins that cells express on their membranes.
What will adhesion differences between different cell types lead to?
Tissue separating or auto organising.
Why do plants have no cell-sorting or differential adhesion?
Do not change neighbours.
What are reasons for the complex plant morphology?
Gene regulatory networks, plant soil interactions, environmental conditions, ecological interactions.
What is Auxin?
A signal that gives cells instructions (hormone).
What is the polarised flows of auxin?
Auxin moves through specialised membrane transporters.
What are auxin gradients instructive for?
Development.
What do small G-protein interactions give rise to?
Polarity.
What is an essential element of G-protein interactions?
Fast cytosolic diffusion, slow membrane diffusion.
What steers the cytoskeleton?
Small G-proteins Rho, Rac and Cdc42.
