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Calcium-mediated structural changes of native nuclear pore complexes monitored by time-lapse atomic force microscopy
D Stoffler1, K N Goldie, B Feja
1University of Basel, Basel, CH-4056, Switzerland.
Journal of Molecular Biology
|April 7, 1999
Summary
Nuclear pore complexes (NPCs) undergo calcium-mediated structural changes, opening and closing their nuclear baskets. However, the central transporter remains insensitive to calcium without ATP, suggesting distinct regulatory mechanisms for nucleocytoplasmic transport.
Area of Science:
- Cell biology
- Structural biology
- Biophysics
Background:
- Nuclear pore complexes (NPCs) regulate transport between the nucleus and cytoplasm.
- Understanding NPC structural dynamics is key to correlating architecture with function in nucleocytoplasmic transport.
Purpose of the Study:
- To investigate calcium-mediated structural changes in individual nuclear pore complexes (NPCs).
- To determine if the NPC's central transporter is a calcium-sensitive component involved in nucleocytoplasmic transport.
Main Methods:
- Time-lapse atomic force microscopy of native NPCs in buffer.
- Observation of calcium-induced structural alterations, specifically nuclear basket opening and closing.
Main Results:
- Observed calcium-mediated opening (+Ca2+) and closing (-Ca2+) of individual nuclear baskets.
- The nuclear basket's distal ring may function as an iris-like diaphragm.
- Cytoplasmic plugging/unplugging of NPCs is calcium-insensitive in the absence of ATP.
Conclusions:
- Nuclear basket structure is dynamically regulated by calcium.
- The central transporter's role in calcium-sensitive nucleocytoplasmic transport is unlikely in the absence of ATP.