Two proteins are normally found in the cytosol. They are involved in DNA double strand break
repair. When DNA damage is detected, they enter the nucleus and locate on the DNA to fix it.
After the process is complete, they exit the nucleus. Explain how the proteins are activated and
their entry into and exit from the nucleus.
Solution
Different proteins involved in such functions may undergo activation and transport by different
mechanisms. I\'ll describe the most commonly used mechanism. When DNA double strand break
is detected, lets say during the cell-cycle checkpoints, the cyclin-dependent kinases
phosphorylate repairing proteins, causing them to get activated. The phosphorylated, activated
protein may be recognized by transporter proteins that traffick them to the nuclear compartment.
During the repairing process, the phosphorylated proteins would usually lose the phosphate (such
as during trade-offs for the energy required for the repair, or another accessory protein involved
in repair may cause de-phosphorylation). The repair protein, devoid of its phosphate group, may
then be transported out of the nucleus back into the cytosol..
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Two proteins are normally found in the cytosol. They are involved in .pdf
1. Two proteins are normally found in the cytosol. They are involved in DNA double strand break
repair. When DNA damage is detected, they enter the nucleus and locate on the DNA to fix it.
After the process is complete, they exit the nucleus. Explain how the proteins are activated and
their entry into and exit from the nucleus.
Solution
Different proteins involved in such functions may undergo activation and transport by different
mechanisms. I'll describe the most commonly used mechanism. When DNA double strand break
is detected, lets say during the cell-cycle checkpoints, the cyclin-dependent kinases
phosphorylate repairing proteins, causing them to get activated. The phosphorylated, activated
protein may be recognized by transporter proteins that traffick them to the nuclear compartment.
During the repairing process, the phosphorylated proteins would usually lose the phosphate (such
as during trade-offs for the energy required for the repair, or another accessory protein involved
in repair may cause de-phosphorylation). The repair protein, devoid of its phosphate group, may
then be transported out of the nucleus back into the cytosol.
