Role of Nesprin-2 and RanBP2 in BICD2-associated brain developmental disorders

Area of Science:

• Neuroscience
• Cell Biology
• Developmental Biology

Background:

• Bicaudal D2 (BICD2) is crucial for intracellular transport via cytoplasmic dynein.
• Mutations in BICD2 cause spinal muscular atrophy with intellectual disability (SMA-LED2) and brain developmental defects.
• BICD2's role in brain development, particularly concerning its mutations, is not fully understood.

Purpose of the Study:

• To investigate the relationship between BICD2 mutations and their impact on brain development.
• To elucidate the competing interactions of BICD2 with RanBP2 and Nesprin-2 at the nuclear envelope.
• To determine how these interactions regulate nuclear and neuronal migration.

Main Methods:

• In vitro biochemical assays to assess BICD2 binding competition.
• In vivo electroporation-mediated brain developmental assays in mice.
• Analysis of BICD2 mutations' effects on nuclear migration and neuronal migration.

Main Results:

• Nesprin-2 and RanBP2 compete for BICD2 binding.
• BICD2 mutations differentially affect binding to RanBP2 and Nesprin-2.
• These binding alterations correlate with defects in nuclear migration in RGPs and neuronal migration.

Conclusions:

• Mutually exclusive interactions between RanBP2-BICD2 and Nesprin-2-BICD2 are critical for interkinetic nuclear migration (INM) in RGPs and neuronal migration.
• Dysregulation of these successive interactions contributes to human brain malformations.
• Understanding these mechanisms provides insight into BICD2-related neurological disorders.