The function of GZMM (granzyme M, Ensembl gene identifier ENSG00000197540) is as follows. Cleaves peptide substrates after methionine, leucine, and norleucine. Physiological substrates include EZR, alpha-tubulins and the apoptosis inhibitor BIRC5/Survivin. Promotes caspase activation and subsequent apoptosis of target cells. {ECO:0000269|PubMed:18523284, ECO:0000269|PubMed:20406824, ECO:0000269|PubMed:8245461}.