Question 1
2..5 pts
Indicate whether each of the following descriptions better applies to COPI- (1), COPII- (2), or
clathrin- (3) coated vesicles. Your answer would be a four-digit number composed of digits 1 to 3
only, e.g. 1322.
( ) They mediate transport from the ER to the cis Golgi network.
( ) Their coat protein forms a three-legged structure called a triskelion.
( ) They are pinched off from their donor compartment by a dynamin collar.
( ) They are involved in retrograde transport in the Golgi apparatus.
3321
1321
2331
2321
3212
Question 2
2..5 pts
Which of the following is NOT correct regarding M6P receptors and KDEL receptors?
They both shuttle back and forth between different membrane-enclosed compartments.
They are both transmembrane proteins.
They both release their soluble binding targets at lower pH.
They both prevent the escape of proteins to the cell exterior by the “default” pathway.
Question 3
2..5 pts
Regulation of the Ci (Cubitus interruptus) protein in the Hedgehog signaling pathway is
reminiscent of that of β-catenin in the Wnt pathway. Which of the following features is shared
among these two proteins?
Both proteins are ubiquitylated when the signal (Hedgehog or Wnt) is present.
Both proteins are able to enter the nucleus only in the absence of the signal.
,Both proteins can be phosphorylated by GSK3 and CK1 in the absence of the signal.
Both proteins are fully degraded by the proteasome in the absence of the signal.
None of the above.
Question 4
2..5 pts
Consider two N-linked oligosaccharide chains on the same protein. The first chain contains three
mannose residues and three negatively charged sialic acid residues, as well as other residues. The
second chain contains only two N-acetylglucosamine and eight mannose residues. Which chain
seems to have been added to the protein such that it is NOT fully accessible to the processing
enzymes in the Golgi apparatus? Which chain is Endo H-sensitive?
Chain one; chain one
Chain one; chain two
Chain two; chain one
Chain two; chain two
Question 5
2..5 pts
For the α subunit of a trimeric G protein, …
a G-protein-coupled receptor (GPCR) acts as a guanine nucleotide exchange factor (GEF),
whereas a regulator of G protein signaling (RGS) can act as a GTPase-activating protein (GAP).
a GPCR acts as a GAP, whereas an RGS can act as a GEF.
both a GPCR and an RGS can act as a GEF.
both a GPCR and an RGS can act as a GAP.
Question 6
2..5 pts
, In the following diagram showing five parallel signaling pathways downstream of a receptor
tyrosine kinase (RTK) and a G-protein-coupled receptor (GPCR), indicate which boxes (A to E)
correspond to the following proteins.
Cyclic AMP
Protein kinase C
Sos
PI(3,4,5)P3
Ca2+
Question 7
2..5 pts
Proteins of the Src family (e.g. Src, Fyn, Lck, and Hck) have important roles in several signaling
pathways in mammals. A typical Src family protein ...
2..5 pts
Indicate whether each of the following descriptions better applies to COPI- (1), COPII- (2), or
clathrin- (3) coated vesicles. Your answer would be a four-digit number composed of digits 1 to 3
only, e.g. 1322.
( ) They mediate transport from the ER to the cis Golgi network.
( ) Their coat protein forms a three-legged structure called a triskelion.
( ) They are pinched off from their donor compartment by a dynamin collar.
( ) They are involved in retrograde transport in the Golgi apparatus.
3321
1321
2331
2321
3212
Question 2
2..5 pts
Which of the following is NOT correct regarding M6P receptors and KDEL receptors?
They both shuttle back and forth between different membrane-enclosed compartments.
They are both transmembrane proteins.
They both release their soluble binding targets at lower pH.
They both prevent the escape of proteins to the cell exterior by the “default” pathway.
Question 3
2..5 pts
Regulation of the Ci (Cubitus interruptus) protein in the Hedgehog signaling pathway is
reminiscent of that of β-catenin in the Wnt pathway. Which of the following features is shared
among these two proteins?
Both proteins are ubiquitylated when the signal (Hedgehog or Wnt) is present.
Both proteins are able to enter the nucleus only in the absence of the signal.
,Both proteins can be phosphorylated by GSK3 and CK1 in the absence of the signal.
Both proteins are fully degraded by the proteasome in the absence of the signal.
None of the above.
Question 4
2..5 pts
Consider two N-linked oligosaccharide chains on the same protein. The first chain contains three
mannose residues and three negatively charged sialic acid residues, as well as other residues. The
second chain contains only two N-acetylglucosamine and eight mannose residues. Which chain
seems to have been added to the protein such that it is NOT fully accessible to the processing
enzymes in the Golgi apparatus? Which chain is Endo H-sensitive?
Chain one; chain one
Chain one; chain two
Chain two; chain one
Chain two; chain two
Question 5
2..5 pts
For the α subunit of a trimeric G protein, …
a G-protein-coupled receptor (GPCR) acts as a guanine nucleotide exchange factor (GEF),
whereas a regulator of G protein signaling (RGS) can act as a GTPase-activating protein (GAP).
a GPCR acts as a GAP, whereas an RGS can act as a GEF.
both a GPCR and an RGS can act as a GEF.
both a GPCR and an RGS can act as a GAP.
Question 6
2..5 pts
, In the following diagram showing five parallel signaling pathways downstream of a receptor
tyrosine kinase (RTK) and a G-protein-coupled receptor (GPCR), indicate which boxes (A to E)
correspond to the following proteins.
Cyclic AMP
Protein kinase C
Sos
PI(3,4,5)P3
Ca2+
Question 7
2..5 pts
Proteins of the Src family (e.g. Src, Fyn, Lck, and Hck) have important roles in several signaling
pathways in mammals. A typical Src family protein ...
