Exposure of zebrafish nuclei to cytosol isolated from eggs at metaphase of mitosis resulted in phosphorylation of NEP55 and L68 proteins by cyclin-dependent kinase 2. NEP55 is a protein of the inner nuclear membrane, and L68 is a protein of the nuclear lamina. What is the most likely role of phosphorylation of these proteins in the process of mitosis?
A) They enable the attachment of the spindle microtubules to kinetochore regions of the centromere.
B) They are involved in chromosome condensation.
C) They are involved in the disassembly of the nuclear envelope.
D) They assist in the migration of centrosomes to opposite sides of the nucleus.

Question

Quizplus · Accepted Answer

The phosphorylation of NEP55 and L68 proteins by cyclin-dependent kinase 2 is likely involved in the disassembly of the nuclear envelope, which is a crucial step in mitosis. This allows the chromosomes to separate and move towards opposite poles of the cell. Phosphorylation of these proteins may facilitate the breakdown of the nuclear envelope by modifying their interactions with other nuclear envelope proteins or with chromatin.

Exposure of Zebrafish Nuclei to Cytosol Isolated from Eggs at Metaphase