receptor and intracellular signalling Flashcards
cells can sense the environment and
react
example of a cell sensing its environment and reacting
macrophages sniff the pathogen and hunt it down: candida albicans release molecules which the macrophages can sense
two types of signalling
via phosphorylation and dephopshorylation and signalling via GTP binding proteins
protein kinases can
get phosphorylated themselves and this amplifies and can spread the signalling to other pathways since protein kinases add phosphate groups to things to make them more reactive
kinases often form a
signalling cascade
phosphorylated kinases and phosphates can
control the activity of effector proteins
signalling via kinases and phosphatases
signal enter and this causes APP to lose a phosphate group and this joins the protein which becomes active and this releases a signal out. To deactivate this protein the phosphatase will cause the protein to lose the phosphate and it will become dormant
phosphatases
an enzyme that removes phosphate groups from a protein
30% of all human proteins
carry a phosphate group
how many kinases and protein phosphates in human
520 kinases
150 protein phosphates
signalling via GTP-binding proteins
signal comes in and GEF causes GPP to to be lost and GTP is now attached causing the molecule to become active. When the G protein needs to stop cascade effects in the cell, GTP will become GDP and this will deactivate the protein
G proteins are molecular
switches
what activates G proteins
guanine nucleotide exchange factor (GEF).
what inactivates G proteins
GTPase activating protein (GAP)
simple intracellular signalling pathway
extracellular signal molecule forms a complex with the receptor in the plasma membrane. This activates numerous intracellular signalling proteins and these activate different effector proteins and cause various reactions like altered metabolism, altered gene expression and altered cell shape or movement
