9.4 signal transduction through receptor kinases Flashcards
what type of receptor protein kinase is found in animals
receptor tyrosine kinases
what type of receptor protein kinase is found in plants
serine-threonine kinases
receptor tyrosine kinases in animals can recognize hydrophilic ligands and influence
the cell cycle, cell migration, cell metabolism and cell proliferation
since receptor tyrosine kinases are involved in growth, alterations of receptor kinases and their signaling pathways can lead to
cancer
structure of a receptor tyrosine kinase
a single transmembrane domain
extracellular ligand-binding domain
intracellular kinase domain
the function of the single transmembrane domain in RTK’s
anchors the RTK in the membrane
the function of the intracellular kinase domain of an RTK
contains the catalytic site of the receptor, acts as a protein kinase
RTK’s are activated by
autophosphorylation
the association of 2 receptor-ligand complexes in RTK’s
dimerization
Phosphotyrosine domains can mediate
protein-protein interactions
bind to phosphotyrosine but do not participate in the signal transduction pathway
adapter proteins
what do adapter proteins do
act as a link between the receptor and the proteins that initiate downstream signaling events
a chemical that stimulates cell division
mitogen
MAP kinases stand for
mitogen-activated protein kinases
what activates MAP kinases
phosphorylation cascade or kinase cascade (signaling nodule)
organizes kinase cascade into a single protein complex
scaffold proteins
scaffold proteins bind to
each individual kinase
small G protein that links the RTK and MAP kinase cascade
Ras Protein
function of Ras protein
acts as a molecular switch to link external signals to internal signal transduction pathways
Ras proteins are active when bound to
GTP
Ras proteins are inactive when bound to
GDP
molecular switch of Ras protein is switched on when
GDP is exchanged for GTP via GEF’s (guanine exchaning factors)
molecular switch of Ras protein is turned off by
Ras hydrolyzing GTP to GDP
