MYSM1,　a　deubiquitinating　enzyme,　plays　a　pivotal　role　in　diverse　biological　processes.　Both　MYSM1　knockout　mice　and　patients　with　Mysm1　gene　mutations　exhibit　developmental　abnormalities　across　multiple　tissues　and　organs.　Serving　as　a　crucial　regulator,　MYSM1　influences　stem　cell　function,　immune　responses,　and　the　pathogenesis　of　diverse　diseases.　This　review　comprehensively　details　MYSM1’s　deubiquitinating　activities　in　both　the　nucleus　and　cytoplasmic　compartments,　its　effects　on　stem　cell　proliferation,　differentiation,　and　immune　cell　function,　and　its　involvement　in　cancer,　aging,　and　depression.　The　high　sequence　homology　between　murine　and　human　MYSM1,　along　with　similar　phenotypes　observed　in　Mysm1-deficient　models,　provides　valuable　insights　into　the　etiology　of　human　Mysm1-deficiency　syndromes.　This　review　aims　to　offer　a　foundation　for　future　comprehensive　research　on　MYSM1.　©　2024　by　the　authors.