HRSP12 (heat-responsive protein 12), also known as PSP, P14.5 or UK114, is a 137 amino acid protein that belongs to the UPF0076 (UK114) family and is expressed primarily in liver and kidney. Localized to the cytoplasm in highly differentiated cells and to the nucleus in less differentiated cells, HRSP12 functions as an endoribonuclease that inhibits translation by cleaving mRNA. Specifically, HRSP12 cleaves phosphodiester bonds in single-stranded mRNA, thereby breaking the mRNA and preventing protein synthesis. HRSP12 exists as a homotrimer and may be a tumor antigen involved in malignant neoplasms. This suggests a possible role in carcinogenesis.
