Schwann cells (SCs) sort and myelinate peripheral axons, and impairments in either process can cause long-term disability. There are no therapeutic strategies for targeting SC dysfunction, underscoring the need to investigate mechanisms of sorting and myelination. Both processes require highly motile SC cytoplasmic protrusions, but the basis of this motility is unclear. I propose to harness mouse genetics and advanced imaging techniques to probe mechanisms underlying the motility of SC protrusions during both sorting and myelination. This work aims to advance our understanding of these key developmental processes within the peripheral nervous system and inform treatment options for SC diseases.