“…Matthew R. Alexander , David G. Harrison I n this issue of Circulation Research, He et al 1 demonstrate a previously undefined role for the cysteine protease LGMN (legumain) in CD4 + (Cluster of Differentiation 4 + ) helper T cells, and specifically regulatory T cells (Tregs), in the pathogenesis of hypertension. LGMN, also known as asparaginyl endopeptidase, is an endosomal and lysosomal cysteine protease that cleaves asparagine residues of proteins such as matrix metalloproteinases, cathepsins, and fibronectin.…”