Question 1

Which of the following is cleaved by regulated intramembrane proteolysis (RIP) ?

Accepted Answer

A)  IB
B)  Notch
C)  TGFβ
D)  IB and TGFβ
E)  Notch and TGFβ B

Question 2

Explain why,upon ligand binding,cell-surface receptors are often subjected to receptor-mediated endocytosis.

Accepted Answer

Removal of transmembrane receptors by re...

Question 3

Describe the role of adapter proteins in the activation of Ras by receptor tyrosine kinases.

Accepted Answer

Following dimerization and autophosphorylation of receptor tyrosine kinases,GRB2 and Sos proteins couple the receptor to the inactive Ras·GDP complex.Sos promotes dissociation of GDP from Ras,allowing GTP to bind.Sos acts as a guanine nucleotide exchange factor (GEF),which helps convert inactive Ras·GDP to active Ras·GTP.The Ras·GTP complex can then activate downstream effector molecules.

Question 4

What feature allows TGFβ signaling molecules to be quickly mobilized?

Accepted Answer

TGFβ signaling molecules are s...

Question 5

Compare and contrast the mechanisms by which SHP1 and SOCS proteins modulate erythropoietin signaling.

Accepted Answer

SHP1 and SOCS are both induced by negati...

Question 6

Which protein stabilizes an intermediate in the Ras GTP hydrolysis reactions?

Accepted Answer

A)  Sos
B)  GRB2
C)  RTK
D)  Raf

Question 7

By what mechanism does PI-3 phosphate promote activation of protein kinase B (PKB) ?

Accepted Answer

A)  recruiting PKB to the plasma membrane
B)  recruiting the activating kinase PDK1 to the plasma membrane
C)  releasing inhibition of the catalytic site by the PH domain
D)  the first and second answers are correct
E)  all of the above

Question 8

Which of the following are enzyme pairs that catalyze opposite reactions?

Accepted Answer

A)  MEK and MAP kinase
B)  NF-B and I-B
C)  PI-3 kinase and PTEN phosphatase
D)  JAKs and STATs
E)  none of the above

Question 9

Serum response factor (SRF) is phosphorylated by:

Accepted Answer

A)  MEK.
B)  MAP kinase.
C)  p90ᴿˢᴷ.
D)  Raf.
E)  Ras.

Question 10

Ras is a(n) :

Accepted Answer

A)  adapter protein.
B)  guanine nucleotide exchange factor.
C)  kinase.
D)  protease.
E)  none of the above

Question 11

NF-B signaling is important in:

Accepted Answer

A)  development.
B)  immunity.
C)  inflammation.
D)  immunity and inflammation.
E)  all of the above

Question 12

Binding of erythropoietin to its extracellular receptor engages which of the following signaling pathways?

Accepted Answer

A)  JAK/STAT
B)  Ras/MAP kinase
C)  PI-3 kinase
D)  all of the above
E)  none of the above

Question 13

A gain-of-function mutation in which of the following would promote malignancy in cells whose proliferation is inhibited by TGFβ?

Accepted Answer

A)  co-Smad
B)  I-Smad
C)  R-Smad
D)  all of the above
E)  none of the above

Question 14

Which of the following is NOT true about the role of adapter proteins in the activation of Ras by receptor tyrosine kinases?

Accepted Answer

A)  Following dimerization and autophosphorylation of receptor tyrosine kinases,GRB2 and Sos proteins couple to the receptor.
B)  GRB2 and Sos proteins couple the receptor to the inactive Ras·GDP complex.
C)  GRB2 interacts with Sos via its SH3 domain.
D)  Sos acts as a GAP,which helps convert Ras·GDP to active Ras·GTP.

Question 15

Which of the following mechanisms is NOT used to terminate cytokine signaling and the JAK/STAT pathway?

Accepted Answer

A)  transcription of SOCS proteins
B)  dephosphorylation of phosphotyrosine residues
C)  heterodimerization of cytokine receptors
D)  receptor internalization

Question 16

Many PTB-containing proteins act as docking sites for multiple proteins.If these proteins are involved in the RTK signal transduction pathway,they most likely:

Accepted Answer

A)  contain GRB2 domains.
B)  are involved in autophosphorylation of the RTK.
C)  are phosphorylating the receptor and the docking protein.
D)  are adopting a different conformation (shape) to expand the pathways affected by ligand binding.

Question 17

A loss-of-function mutation in which of the following would inhibit TGFβ signaling?

Accepted Answer

A)  I-Smad
B)  R-Smad
C)  Ski
D)  SnoN
E)  all of the above B

Question 18

Predict the consequences of a temperature-sensitive mutation in which phosphorylation of the β-catenin protein is blocked.Above the permissive temperature:

Accepted Answer

A)  β-catenin levels will increase and β-catenin will be constitutively active.
B)  β-catenin levels will increase and β-catenin will be inactive.
C)  β-catenin levels will decrease.
D)  β-catenin will remain constant but cells will be unresponsive to Wnt signaling.

Question 19

How can multiple MAP kinase pathways be segregated when they share a common component,like a downstream kinase?

Accepted Answer

A)  formation of pathway-specific complexes assembled on molecular scaffolds
B)  activation of different small G proteins
C)  differential activation of activation lip tyrosines
D)  phosphorylation of PTB-containing proteins

Question 20

Latent TGFβ is converted to mature TGFβ by:

Accepted Answer

A)  dephosphorylation.
B)  phosphorylation.
C)  proteolysis.
D)  translocation.
E)  none of the above

Exam 15: Signaling Pathways That Control Gene Activity

Which of the following is cleaved by regulated intramembrane proteolysis (RIP) ?

Correct Answer
verified
B

Explain why,upon ligand binding,cell-surface receptors are often subjected to receptor-mediated endocytosis.

Correct Answer
verified
Removal of transmembrane receptors by re...
View Answer

Describe the role of adapter proteins in the activation of Ras by receptor tyrosine kinases.

What feature allows TGFβ signaling molecules to be quickly mobilized?

Correct Answer
verified
TGFβ signaling molecules are s...
View Answer

Compare and contrast the mechanisms by which SHP1 and SOCS proteins modulate erythropoietin signaling.

Correct Answer
verified
SHP1 and SOCS are both induced by negati...
View Answer

Which protein stabilizes an intermediate in the Ras GTP hydrolysis reactions?

Correct Answer
verified

By what mechanism does PI-3 phosphate promote activation of protein kinase B (PKB) ?

Correct Answer
verified

Which of the following are enzyme pairs that catalyze opposite reactions?

Correct Answer
verified

Serum response factor (SRF) is phosphorylated by:

Correct Answer
verified

Ras is a(n) :

Correct Answer
verified

NF-B signaling is important in:

Correct Answer
verified

Binding of erythropoietin to its extracellular receptor engages which of the following signaling pathways?

Correct Answer
verified

A gain-of-function mutation in which of the following would promote malignancy in cells whose proliferation is inhibited by TGFβ?

Correct Answer
verified

Which of the following is NOT true about the role of adapter proteins in the activation of Ras by receptor tyrosine kinases?

Correct Answer
verified

Which of the following mechanisms is NOT used to terminate cytokine signaling and the JAK/STAT pathway?

Correct Answer
verified

Many PTB-containing proteins act as docking sites for multiple proteins.If these proteins are involved in the RTK signal transduction pathway,they most likely:

Correct Answer
verified

A loss-of-function mutation in which of the following would inhibit TGFβ signaling?

Correct Answer
verified
B

Predict the consequences of a temperature-sensitive mutation in which phosphorylation of the β-catenin protein is blocked.Above the permissive temperature:

Correct Answer
verified

How can multiple MAP kinase pathways be segregated when they share a common component,like a downstream kinase?

Correct Answer
verified

Latent TGFβ is converted to mature TGFβ by:

Correct Answer
verified

Exam 15: Signaling Pathways That Control Gene Activity

Which of the following is cleaved by regulated intramembrane proteolysis (RIP) ?

Correct AnswerverifiedB

Explain why,upon ligand binding,cell-surface receptors are often subjected to receptor-mediated endocytosis.

Correct AnswerverifiedRemoval of transmembrane receptors by re...View AnswerShow Answer

Describe the role of adapter proteins in the activation of Ras by receptor tyrosine kinases.

What feature allows TGFβ signaling molecules to be quickly mobilized?

Correct AnswerverifiedTGFβ signaling molecules are s...View AnswerShow Answer

Compare and contrast the mechanisms by which SHP1 and SOCS proteins modulate erythropoietin signaling.

Correct AnswerverifiedSHP1 and SOCS are both induced by negati...View AnswerShow Answer

Which protein stabilizes an intermediate in the Ras GTP hydrolysis reactions?

Correct AnswerverifiedShow Answer

By what mechanism does PI-3 phosphate promote activation of protein kinase B (PKB) ?

Correct AnswerverifiedShow Answer

Which of the following are enzyme pairs that catalyze opposite reactions?

Correct AnswerverifiedShow Answer

Serum response factor (SRF) is phosphorylated by:

Correct AnswerverifiedShow Answer

Ras is a(n) :

Correct AnswerverifiedShow Answer

NF-B signaling is important in:

Correct AnswerverifiedShow Answer

Binding of erythropoietin to its extracellular receptor engages which of the following signaling pathways?

Correct AnswerverifiedShow Answer

A gain-of-function mutation in which of the following would promote malignancy in cells whose proliferation is inhibited by TGFβ?

Correct AnswerverifiedShow Answer

Which of the following is NOT true about the role of adapter proteins in the activation of Ras by receptor tyrosine kinases?

Correct AnswerverifiedShow Answer

Which of the following mechanisms is NOT used to terminate cytokine signaling and the JAK/STAT pathway?

Correct AnswerverifiedShow Answer

Many PTB-containing proteins act as docking sites for multiple proteins.If these proteins are involved in the RTK signal transduction pathway,they most likely:

Correct AnswerverifiedShow Answer

A loss-of-function mutation in which of the following would inhibit TGFβ signaling?

Correct AnswerverifiedB

Predict the consequences of a temperature-sensitive mutation in which phosphorylation of the β-catenin protein is blocked.Above the permissive temperature:

Correct AnswerverifiedShow Answer

How can multiple MAP kinase pathways be segregated when they share a common component,like a downstream kinase?

Correct AnswerverifiedShow Answer

Latent TGFβ is converted to mature TGFβ by:

Correct AnswerverifiedShow Answer

Correct Answer
verified
B

Correct Answer
verified
Removal of transmembrane receptors by re...
View Answer

Correct Answer
verified
TGFβ signaling molecules are s...
View Answer

Correct Answer
verified
SHP1 and SOCS are both induced by negati...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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B

Correct Answer
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Correct Answer
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Correct Answer
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