The membrane palmitoylated protein, MPP6, is involved in myelin formation in the mouse peripheral nervous system

Area of Science:

• Neuroscience
• Cell Biology
• Molecular Biology

Background:

• Schwann cells in the peripheral nervous system (PNS) contain a membrane skeletal complex involving protein 4.1G, membrane palmitoylated protein 6 (MPP6), Lin7, and cell adhesion molecule 4 (CADM4).
• This complex, particularly MPP6, Lin7, and CADM4, is transported to Schmidt-Lanterman incisures (SLIs) by protein 4.1G.

Purpose of the Study:

• To investigate the role of MPP6 in myelin structure and protein complex formation within the PNS.
• To elucidate the function of the MPP6-Lin7 complex in Schwann cells and myelin maintenance.

Main Methods:

• Generation and analysis of MPP6-deficient mice.
• Immunohistochemistry and western blotting to assess protein localization and levels.
• Electron microscopy to evaluate sciatic nerve myelin structure.
• Tail-suspension test to assess motor activity.

Main Results:

• In MPP6-deficient mice, Lin7 was significantly reduced in SLIs, while CADM4 and 4.1G localization and amounts remained unchanged.
• No significant impairment in motor activity was observed in MPP6-deficient mice.
• Electron microscopy revealed significantly thicker myelin in the internodes of sciatic nerves from MPP6-deficient mice compared to wild-type controls.

Conclusions:

• The MPP6-Lin7 protein complex plays a regulatory role in myelin formation and structure within the PNS.
• MPP6 deficiency alters myelin thickness, suggesting its involvement in myelin homeostasis.