Stmp1, or short transmembrane protein 1, is a mitochondrial micropeptide encoded by lncRNA 1810058I24Rik in mammals. It plays crucial roles in multiple biological processes, such as promoting mitochondrial fission, enhancing cell cycle progression, and regulating cholesterol metabolism in specific organisms. In cancer, it is involved in promoting tumor metastasis and cell proliferation. In retinal development, it contributes to cell differentiation, and in Coxiella burnetii, it helps regulate cholesterol in the intracellular niche [1,2,3,4].

In in vivo studies using xenograft mouse models, Stmp1 silencing inhibited tumor metastasis, demonstrating its role in cancer metastasis [1]. In neonatal murine retinas, overexpressing Stmp1 promoted the differentiation of bipolar, amacrine, and Müller cells, while in mouse models of retinal ischemia/reperfusion injury, Stmp1 deficiency protected retinal ganglion cells by attenuating microglia activation [2,5].

In conclusion, Stmp1 has diverse essential functions, from promoting tumor metastasis and cell proliferation in cancer to contributing to retinal cell differentiation and regulating cholesterol in intracellular niches. Gene knockout models in mice have been instrumental in revealing its role in cancer metastasis and retinal-related disease conditions, offering potential therapeutic targets for treating metastases and retinal-associated neurodegenerative diseases.