Olfactomedin-1 Has a V-shaped Disulfide-linked Tetrameric Structure

Area of Science:

• Biochemistry
• Structural Biology
• Neuroscience

Background:

• Olfactomedin-1 (Olfm1) is a neuronal glycoprotein vital for nervous system development.
• It mediates cell signaling by binding secreted proteins and cell surface receptors.

Purpose of the Study:

• To determine the quaternary structure and architecture of full-length Olfactomedin-1 (Olfm1).
• To elucidate the structural basis for Olfm1's function in cell signaling.

Main Methods:

• X-ray crystallography
• Solution scattering (SAXS/SANS)
• Analytical ultracentrifugation (AUC)
• Electron microscopy (EM)

Main Results:

• Full-length Olfm1 forms a stable, disulfide-linked tetramer with a distinctive V-shaped architecture.
• The N-terminal domains form the base of the 'V', while coiled-coil and β-propeller domains form the legs.
• Olfm1 structure is stabilized by calcium, similar to myocilin.

Conclusions:

• The dimer-of-dimers architecture suggests Olfm1 functions in clustering receptors to regulate signaling pathways.
• This structural insight is applicable to other members of the olfactomedin domain superfamily.