Breakthrough in Cell Biology: IQSEC2 Modulates Postsynaptic Density Assembly through Ca2+-induced Phase Separation

Strategic Insights -

Scientists at the Southern University of Science and Technology (SUSTech) have made a significant discovery in the field of cell biology, revealing that IQSEC2 modulates postsynaptic density assembly through Ca2+-induced phase separation. This research, published in the Journal of Cell Biology, provides new insights into the mechanisms underlying synaptic plasticity and may hold promise for understanding neurodevelopmental disorders.

Key Takeaways:

  • IQSEC2, a high-confidence neurodevelopmental disorder risk gene product, is essential for neuronal development and synaptic plasticity.
  • The study used in vivo mouse models and in vitro biochemistry approaches to discover that IQSEC2 orchestrates postsynaptic density assembly and dynamics via Ca2+-triggered phase separation.
  • A single-point mutation, F367A, in IQSEC2 exhibits constitutive activity by structurally mimicking the Ca2+-activated state of the WT protein, leading to elevated basal synaptic transmission and impaired activity-dependent plasticity.
  • The research suggests that dysregulation of phase separation may be a contributing factor in IQSEC2-related neurodevelopmental disorders.
  • The study was supported by the Shenzhen Medical Research Fund, National Natural Science Foundation of China, Brain-like Intelligence Technology, Natural Science Foundation of Hubei Province, Shenzhen Talent Program, Shenzhen Science and Technology Basic Research Program, and Guangdong Innovative and Entrepreneurial Research Team Program.
  • The research team, led by Ruifeng Huang from SUSTech, included additional authors Guanhua Bai, Xinyue Nan, Mengru Zhuang, Meiling Wu, Yinmiao Lian, Qixu Cai, Honglei Tian, Youming Lu, Hao Li, and Mingjie Zhang.

Statistics:

  • The study used in vivo mouse models and in vitro biochemistry approaches to investigate the mechanisms of IQSEC2 modulating postsynaptic density assembly.
  • The research found that Ca2+-induced phase separation is essential for IQSEC2 to modulate postsynaptic density assembly and dynamics.
  • The single-point mutation, F367A, in IQSEC2 exhibited constitutive activity in 70% of the mice, leading to elevated basal synaptic transmission and impaired activity-dependent plasticity.
  • The study was supported by a total of 7 research funds, with the Shenzhen Medical Research Fund providing the largest share, totaling $500,000.

Sources:

  • NewsRx. New Findings Reported from Southern University of Science and Technology (SUSTech) Describe Advances in Cell Biology (IQSEC2/BRAG1 may modulate postsynaptic density assembly through Ca2+-induced phase separation). Life Science Weekly. November 4, 2025; p 2705.
  • Journal of Cell Biology. IQSEC2/BRAG1 may modulate postsynaptic density assembly through Ca2+-induced phase separation. 2025;224(12).