Cell signalling Flashcards
What is the basic concept of cell signalling?
A chemical signal is released by once cell and is recognised by another. It usually involves a receptor molecule that recognises the signal in a highly specific manner and allows the recipient cell to make a characteristic response.
Why is cell signalling important?
It is essential for coordination of cell behaviour, identify and interact with cells of the correct mating type in sexual reproduction in single cell organisms, and multicellular organisms depend on it for correct development, tissue maintenance and homeostasis.
What can mis-regulation of cell signalling in development cause?
Cancer.
What are the four types of cell signalling?
Endocrine, paracrine, neuronal and contact-dependent.
How does endocrine cell signalling work?
Hormones released into the bloodstream that travel to the target cell.
How does paracrine cell signalling work?
Mediators are released from a signalling cell and reach target cells.
How does neuronal cell signalling work?
Neurotransmitters are released from a neurone that act on a target cell.
How does contact-dependent cell signalling work?
A membrane bound signalling molecule is attached to the signalling cell and the target cell needs to be close enough for the receptor to bind.
How are two specialised cell types formed in the nervous system during development?
In an organised manner through contact-mediated cell signalling, involve delta (signal) and notch (receptor)>
In Delta-Notch signalling, what does low levels of neurogenin promote?
Low levels of delta expression.
What is the delta-notch signalling state in unspecialised epithelial cells?
They are all equivalent - they signal to their neighbours to maintain low levels of neurogenin.
What do higher levels of Delta in some epithelial cells result in?
Signals to surrounding cells to prevent neurogenin expression. It stops them from differentiating as neurons and reduces their expression of delta.
What happens in cells not receiving a delta signal?
Neurogenin levels increase that allows the expression of factors such as Neuro D that initiate neuronal differentiation.
What are ways to ensure local signals don’t act too far from their origin?
Rapid degradation, binding to inhibitory proteins/molecules and binding to the ECM.
What is the Ach receptor on cardiac and salivary glands?
GPCR.
