9.4 signal transduction through receptor kinases

Question 1

what type of receptor protein kinase is found in animals

Answer 1

receptor tyrosine kinases

Question 2

what type of receptor protein kinase is found in plants

Answer 2

serine-threonine kinases

Question 3

receptor tyrosine kinases in animals can recognize hydrophilic ligands and influence

Answer 3

the cell cycle, cell migration, cell metabolism and cell proliferation

Question 4

since receptor tyrosine kinases are involved in growth, alterations of receptor kinases and their signaling pathways can lead to

Answer 4

cancer

Question 5

structure of a receptor tyrosine kinase

Answer 5

a single transmembrane domain
extracellular ligand-binding domain
intracellular kinase domain

Question 6

the function of the single transmembrane domain in RTK’s

Answer 6

anchors the RTK in the membrane

Question 7

the function of the intracellular kinase domain of an RTK

Answer 7

contains the catalytic site of the receptor, acts as a protein kinase

Question 8

RTK’s are activated by

Answer 8

autophosphorylation

Question 9

the association of 2 receptor-ligand complexes in RTK’s

Answer 9

dimerization

Question 10

Phosphotyrosine domains can mediate

Answer 10

protein-protein interactions

Question 11

bind to phosphotyrosine but do not participate in the signal transduction pathway

Answer 11

adapter proteins

Question 12

what do adapter proteins do

Answer 12

act as a link between the receptor and the proteins that initiate downstream signaling events

Question 13

a chemical that stimulates cell division

Answer 13

mitogen

Question 14

MAP kinases stand for

Answer 14

mitogen-activated protein kinases

Question 15

what activates MAP kinases

Answer 15

phosphorylation cascade or kinase cascade (signaling nodule)

Question 16

organizes kinase cascade into a single protein complex

Answer 16

scaffold proteins

Question 17

scaffold proteins bind to

Answer 17

each individual kinase

Question 18

small G protein that links the RTK and MAP kinase cascade

Answer 18

Ras Protein

Question 19

function of Ras protein

Answer 19

acts as a molecular switch to link external signals to internal signal transduction pathways

Question 20

Ras proteins are active when bound to

Answer 20

GTP

Question 21

Ras proteins are inactive when bound to

Answer 21

GDP

Question 22

molecular switch of Ras protein is switched on when

Answer 22

GDP is exchanged for GTP via GEF’s (guanine exchaning factors)

Question 23

molecular switch of Ras protein is turned off by

Answer 23

Ras hydrolyzing GTP to GDP