Mechanoresponsive modulation of nuclear pore complex structure and function by O-GlcNAc

Area of Science:

• Cell Biology
• Molecular Biology
• Biophysics

Background:

• Nuclear pore complexes (NPCs) regulate transport between the nucleus and cytoplasm.
• The precise mechanisms controlling NPC selective permeability across different cell types and conditions are not fully understood.
• O-linked N-acetylglucosamine (GlcNAc) modification of nucleoporins is a dynamic post-translational modification.

Purpose of the Study:

• To investigate how NPC selective permeability is modulated in different cellular contexts.
• To determine the role of O-linked N-acetylglucosamine (GlcNAc) modification in regulating NPC function.
• To explore the mechanosensitive nature of NPC permeability and its regulation by GlcNAc.

Main Methods:

• Utilized conditional genetic tools to control nucleoporin GlcNAcylation.
• Compared NPC diffusion barrier strength across various cell types, including cultured neurons.
• Investigated the effect of substrate stiffness and osmotic shock on NPC permeability and GlcNAcylation.
• Monitored the recruitment of O-linked N-acetylglucosamine transferase to NPCs.

Main Results:

• NPC diffusion barrier strength varies by cell type, being most stringent in neurons.
• GlcNAc modification of nucleoporins directly modulates NPC permeability.
• Nucleoporin GlcNAcylation is mechanosensitive, increasing on stiff substrates and leading to NPC dilation.
• GlcNAcylation levels decrease NPC constriction during osmotic stress.

Conclusions:

• Cells utilize O-linked N-acetylglucosamine (GlcNAc) to dynamically adjust NPC permeability.
• NPC permeability is responsive to mechanical inputs and osmotic challenges via GlcNAc modification.
• This regulatory mechanism allows cells to maintain nuclear transport homeostasis under varying environmental conditions.