Protein Phosphatase 2ACα Regulates ATR-Mediated Endogenous DNA Damage Response Against Microcephaly

Area of Science:

• Neuroscience
• Molecular Biology
• Cell Biology

Background:

• Protein Phosphatase 2A (PP2A) is a key enzyme regulating cellular processes through dephosphorylation.
• The role of PP2A in cortical neurogenesis, the development of the cerebral cortex, is not well understood.

Purpose of the Study:

• To investigate the function of PP2A, specifically the PP2ACα subunit, in neuronal development and cortical neurogenesis.
• To elucidate the molecular mechanisms by which PP2A influences neurogenesis and brain size.

Main Methods:

• Neuronal-specific deletion of the Pp2acα gene in mice.
• Analysis of brain size, learning, and memory in knockout mice.
• Investigation of DNA damage, cell signaling pathways (ATR/CHK1), and downstream factors (P53, P21, Bcl2, Bax).

Main Results:

• Neuronal deletion of Pp2acα led to microcephaly, smaller brains, and impaired learning/memory.
• Pp2acα deficiency caused increased endogenous DNA damage and activated ATR/CHK1 signaling.
• Loss of PP2ACα disrupted the interaction with and dephosphorylation of ATR, altering downstream targets and affecting cell proliferation and apoptosis.

Conclusions:

• PP2ACα plays an essential role in the DNA damage response via ATR signaling during neurogenesis.
• Defects in neuronal PP2ACα contribute to microcephaly by disrupting normal cortical development.