Mitochondrial Trafficking and CMT2 Neuropathy

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Mitochondrial Trafficking and CMT 2 Neuropathy

http://www.medicalnewstoday.com/medicalnews.php?newsid=60488

H. Baloh, E. Schmidt, Alan Pestronk, and

Milbrandt

Heriditary neuropathies come in many shapes and sizes. Charcot-Marie-

Tooth type 2 (CMT2) causes degeneration of peripheral sensory and

motor neurons, particularly at the ends of these long axons. Many

cases of CMT2 arise from mutations in a mitochondrial fusion protein

mitofusin 2 (MFN2). This week, Baloh et al. propose that MFN2

mutations cause disease by altering mitochondrial trafficking. The

authors expressed mutant MFN2 in cultured dorsal root ganglion

neurons. Fragmented mitochondria clustered in cell bodies and

proximal axons of these neurons. Time-lapse fluorescence imaging

revealed disrupted mitochondrial trafficking, although ATP

production and mitochondrial oxidative function remained intact.

Likewise, oxidative activity was not disrupted in a muscle biopsy

specimen from a patient with CMT2A. The transport failure may result

from reduced attachment of mitochondria to the microtubule transport

apparatus, thus limiting delivery of energy supplies to long axons.