Centrobin plays a role in the cellular response to DNA damage

Area of Science:

• Cell Biology
• Molecular Biology
• DNA Repair Mechanisms

Background:

• DNA repair proteins are known to localize to centrosomes, and their defects can lead to centrosome abnormalities.
• Centrobin is a centriole-associated protein essential for centriole duplication and microtubule stability.
• Previous research identified centrobin as a potential substrate for ATM/ATR kinases, but its role in DNA damage response (DDR) was unknown.

Purpose of the Study:

• To investigate the involvement of centrobin in the DNA damage response (DDR) pathway.
• To determine if centrobin is phosphorylated upon DNA damage and its functional significance.

Main Methods:

• UV irradiation of cells to induce DNA damage.
• Western blotting and immunoprecipitation to detect centrobin phosphorylation.
• Analysis of centrosome and nuclear matrix localization of phosphorylated centrobin.
• RNA interference (RNAi) to deplete centrobin expression.
• Assessment of microtubule stability, UV sensitivity, and homologous recombination (HR) repair efficiency in centrobin-depleted cells.

Main Results:

• Centrobin undergoes UV-induced phosphorylation, predominantly within the detergent/DNase I-resistant nuclear matrix.
• This phosphorylation is largely dependent on ATR kinase activity.
• Cells depleted of centrobin exhibit impaired DNA damage-induced microtubule stabilization and increased sensitivity to UV radiation.
• Centrobin depletion results in defective homologous recombination (HR) repair, which can be rescued by expressing wild-type centrobin.

Conclusions:

• Centrobin is a novel component of the DNA damage response (DDR) pathway.
• Its phosphorylation by ATR kinases and its role in microtubule stabilization and HR repair highlight its importance in maintaining genomic integrity after DNA damage.