E3L1: Cytoskeleton Flashcards
Which of the following compose “microfilaments”?
a. Actin filaments
b. Microtubules
c. Intermediate filaments
d. Titin
e. Two of the above
A. Actin filaments
Which of the following are associated with the (+) end of actin?
a. Protrusion of lamellapodia
b. CapZ
c. Cofilin
d. Actin Related Protein (ARP) complex
e. A and B
e. A and B
Which of the following can “nucleate” the assembly of an actin filament?
a. Mg2+
b. ARP complexes
c. Ca2+
d.Two of the above
d. 2 of the above (Mg2+ and ARP)
Which of the following are true, regarding actin “treadmilling”?
a. At both the (-) and (+) ends, the rate of addition equals the rate of hydrolysis
b. At the (-) end, the rate of addition is greater than the rate of hydrolysis
c. At the (+) end, the rate of addition is greater than the rate of hydrolysis
d. The actin filament remains stationary
c. At the (+) end, the rate of addition is greater than the rate of hydrolysis
Which of the following are involved in the depolymerization of actin net filaments?
a. CapZ
b. ARP
c. Cofilin binding of Actin-ADP
d. Cofilin binding of Actin-ATP
c.Cofilin binding of Actin-ADP
Which of the following promote angled assembly of actin filaments?
a. ARP
b. Filamin dimers
c. Fimbrin
d. Alpha-actinin
e.Two of the above
e.Two of the above
(ARP and Filamin dimers)
Which of the following proteins are necessary for forming “bundling proteins”? Circle all that apply!
a. Alpha-actinin
b. Fimbrin
c. Filamin
d. Spectrin
A. alpha-actinin
B. Fimbrin
Which of the following bind “aging units” of actin filaments, promoting their depolymerization?
a. Fimbrin
b. Filamin
c. Cofilin
d. Boom-chika-tinalin
C. Cofilin
In contractile bundles (in muscle), which structural protein aligns actin filaments with respect to one another? Circle all that apply.
a. Alpha-actinin
b. Fimbrin
c. ARP
d. Filamin dimers
B. Fimbrin
Note: alpha-actinin is larger than fimbrin, so there is space for myosin II binding!
Which structural protein, inherent to the structure shown, enables actin filaments to align in parallel?
a. Alpha-actinin
B. Fimbrin
C. ARP
D. Filamen dimers
B. Fimbrin (these are microvilli!)
Keratins are selectively expressed in which of the following cell lines?
a. Glial cells
b. Muscle
c. Epithelial cells
d. Neurons
C. epithelial cells
Which of the following are expressed in a tissue specific manner?
a. Actin filaments
b. Intermediate filaments
c. microtubules
d. Collagen
b. intermediate filaments
