Stmp1, short for short transmembrane protein 1, is a mitochondrial micropeptide encoded by lncRNA 1810058I24Rik in mammals. It is involved in multiple biological processes. Functionally, it participates in mitochondrial-related functions and is associated with pathways like cell cycle regulation, cell differentiation, and metastasis. It may act as a subunit of mitochondrial respiratory complexes and has significance in both normal biological development and disease-related processes [2,3,5].

In cancer research, gain-and loss-of-function studies, including STMP1 silencing in xenograft mouse models, revealed that STMP1 promotes tumor metastasis by enhancing mitochondrial fission. It increases dynamin-related protein 1 (DRP1) activation, leading to enhanced migration of tumor cells. Treatment with a DRP1 inhibitor abrogated its promotive effects on mitochondrial fission, cell migration, and metastasis [1].

In retinal development, over-expression of Stmp1 in neonatal murine retinas promotes the differentiation of bipolar, amacrine, and Müller cells. Its 15-AA N-terminus is identified as the mitochondrion-targeting sequence [2].

In retinal ischemia/reperfusion injury, deficiency of Stmp1 in mice protects retinal ganglion cells by attenuating microglia activation and the Nlrp3 inflammasome pathway, and its genetic knockout or knockdown promotes mitochondrial fusion [4].

In summary, Stmp1 is crucial for various biological functions, especially those related to mitochondrial activities, cell differentiation, and cell migration. Mouse models with Stmp1 knockout or knockdown have provided valuable insights into its role in cancer metastasis, retinal development, and retinal ischemia/reperfusion injury, suggesting it could be a potential therapeutic target for related diseases [1,2,4].