Mtmr2, short for myotubularin-related protein 2, is a ubiquitously expressed phosphatase. Its preferred substrate is phosphatidylinositol (3,5)-biphosphate, a regulator of membrane homeostasis and vesicle transport. It is involved in pathways related to cell signaling and is associated with various biological processes, with its study often aided by genetic models such as gene knockout mouse models [1,2].

Mutations in Mtmr2 cause autosomal recessive Charcot-Marie-Tooth (CMT) type 4B1, a demyelinating neuropathy. Mtmr2-null mice develop progressive neuropathy characterized by myelin outfolding and recurrent loops at paranodal myelin, and also show depletion of spermatids and spermatocytes leading to azoospermia. Disrupting Mtmr2 in Schwann cells can reproduce the myelin abnormalities. Additionally, Mtmr2 may regulate AKT signalling, as overexpression of Mtmr2 prevents the degradation of the epidermal growth factor receptor (EGFR) and leads to sustained Akt activation [1,2].

In conclusion, Mtmr2 is crucial for maintaining normal function in the peripheral nervous system and spermatogenesis. The Mtmr2-null mouse model has been instrumental in revealing its role in CMT4B1-like neuropathy and associated pathologies, enhancing our understanding of the underlying mechanisms and potentially guiding future therapeutic strategies for related diseases.