Question

Dynamitin is a subunit of the dynactin complex. Its overexpression leads to the disassembly of the complex, and it is therefore considered a dynactin inhibitor. Which of the following processes would happen if dynamitin is overexpressed in a cell?

A. The motile cilia (if any) would stop beating because the axonemal dyneins could not attach to their neighboring microtubules.
B. The Golgi apparatus would fragment and become dispersed because the cytoplasmic dyneins could not associate with the Golgi membranes.
C. The endoplasmic reticulum would collapse because it could not recruit enough kinesins.
D. The nuclear envelope would disintegrate because the nuclear lamins could not interact with the cytoplasmic cytoskeleton.
E. The cortex would lose its integrity because the Arp 2/3 complex would also be inhibited.

Answer 1

Overexpression of dynamitin acts as a dynactin inhibitor, leading to the fragmentation and dispersion of the Golgi apparatus as cytoplasmic dynein would be unable to function properly, affecting cargo movement along microtubules.

Step-by-step explanation:

Overexpression of dynamitin, a subunit of the dynactin complex, leads to its role as a dynactin inhibitor by leading to the disassembly of the complex. This would directly affect processes that rely on dynein, which is a motor protein that moves cargo along microtubules. Thus, the process that would occur as a result of dynamitin overexpression is B. The Golgi apparatus would fragment and become dispersed. This is because cytoplasmic dynein, which associates with the Golgi membranes to help maintain its structure and position within the cell, would be unable to function properly. The other listed processes involve different components of the cytoskeletal system independent of dynactin or are associated with other cellular mechanisms such as actin polymerization and are therefore less likely to be directly affected by dynamitin overexpression.