Sam68 Is Required for DNA Damage Responses via Regulating Poly(ADP-ribosyl)ation

Area of Science:

• Molecular Biology
• Cellular Biology
• Genetics

Background:

• Poly(ADP-ribose) polymerase 1 (PARP1) synthesizes poly(ADP-ribose) (PAR) chains, essential for DNA damage response (DDR).
• The exact mechanisms of PARP1 activation and robust PAR synthesis remain incompletely understood.

Purpose of the Study:

• To identify novel signaling molecules involved in DNA damage-triggered PAR production.
• To elucidate the role of Src-associated substrate during mitosis of 68 kDa (Sam68) in DDR.

Main Methods:

• Cellular and biochemical assays were used to investigate the interaction between Sam68 and PARP1.
• Analysis of Sam68-deleted cell lines and knockout mice subjected to genotoxicity.

Main Results:

• Sam68 was identified as a novel signaling molecule in DDR.
• Sam68 is recruited to DNA lesions and interacts with PARP1, which is critical for PAR production.
• Sam68-deficient cells and animals exhibit hypersensitivity to DNA-damaging agents.

Conclusions:

• Sam68 plays a critical role in DDR by regulating DNA damage-initiated PAR production.
• The interaction between Sam68 and PARP1 is essential for efficient PAR synthesis and DNA repair signaling.