Excited that my 1st PhDwork paper investigating interactions between Schwann cells (SC) & axons in peripheral nerves is out @NatureComms. We found that SC restrict axonal diameters by a mechanism involving a newly identified surface protein: https://www.nature.com/articles/s41467-020-18172-7 –A thread 1/10

2/10 The close association of #Schwanncells & axons involves several signaling molecules & is required for fast (saltatory) propagation and nerve function. However, surprisingly little is known about signaling from SCs toward axons and we investigated novel candidates.

3/10 Adapting protocols from the CNS we biochemically enriched the interface of axons & SCs. Together with @TenzerLab we used #quantitativeproteomics to investigate the axogliasome-enriched fraction. Among others, we found the transmembrane protein CMTM6 & investigated its role.

4/10 By STED microscopy with @ElisaDEste and using cryo-immuno electron microscopy we found that CMTM6 is indeed localized at the SC membrane facing the axon. But what does CMTM6 do at this contact zone?

5/10 At the department of #Neurogenetics @maxplanckpress, we deleted the gene encoding CMTM6 in SCs of mice. Much to our surprise we found in various peripheral nerve types considerably larger diameters of axons, both myelinated and non-myelinated.

6/10 But how about other parameters of the axon/myelin-unit? Deficiency of CMTM6 does not impair axonal sorting or integrity or #myelin biogenesis, suggesting its function is specific to restricting the radial growth of axons.

7/10 Since the 1950s it is known that nerve conduction velocity (NCV) along myelinated fibers shows a linear dependency on axon diameter. So, can we see this in our new mouse model with increased axonal diameters? https://physoc.onlinelibrary.wiley.com/doi/pdf/10.1113/jphysiol.1951.sp004655

8/10 With @RFledrich we found that mice w/o CMTM6 have increased sensory NCV & react faster to thermal stimuli. We checked other parameters that regulate NCV (paranodes,nodes,internodes) & did not detect differences–faster NCV thus appears to arise from larger axonal diameters.

9/10 Together, SCs regulate radial growth of peripheral axons via CMTM6, MAG and probably other adaxonal SC proteins. We look forward to future studies identifying additional proteins with crucial roles in the axon/myelin-unit and research tackling their functional interplay.

10/10 Last but not least: I am very grateful to everyone who contributed to this story & supported us along the way- #TeamworkMakesTheDreamwork! Thx to @SGargareta, @KlausNave, my supervisor @HaukeWerner, all our collaborators, the supportive 3 reviewers & our editor @ElisaFlo04