Cell signalling
The process by which a cell responds to substances outside
the cell through signalling molecules found on the surface of and inside the
cell. Most molecules that lead to cell signalling are chemical substances, such
as hormones, neurotransmitters, and growth factors, that bind to a specific
protein receptor (signalling molecule) on or in a cell. The signals are then
passed from one molecule to another inside the cell, which results in a
specific cell response, such as cell division or cell death. Cell signalling is
important for cells to grow and work normally. Cells that have abnormal signalling
molecules may become cancer cells. Also called signal transduction1.
