Tmprss13, also known as mosaic seine protease large-form (MSPL), is a member of the type II transmembrane serine protease (TTSP) family. It has trypsin-like catalytic activity and is involved in various biological processes. It plays a role in the cell entry of some coronaviruses, such as swine acute diarrhea syndrome coronavirus (SADS-CoV) [1]. It also has implications in cancer progression, like in colorectal cancer where it promotes cell survival, invasion, and resistance to drug-induced apoptosis [2].

In Tmprss13-deficient mice, high levels of Tmprss13 expression were found in the epithelia of the oral cavity, upper digestive tract and skin. The Tmprss13-deficient mice displayed abnormal skin development, leading to a compromised barrier function, as measured by the transepidermal fluid loss rate of newborn mice [3].

In conclusion, Tmprss13 is crucial for processes like virus entry and cancer cell behavior. The Tmprss13-deficient mouse model reveals its importance in epidermal barrier acquisition. Understanding Tmprss13's functions can potentially lead to new strategies in treating virus-related diseases and cancers.