Legumain

This gene encodes a member of the cysteine peptidase family C13 that plays an important role in the endosome/lysosomal degradation system. The encoded inactive preproprotein undergoes autocatalytic removal of the C-terminal inhibitory propeptide to generate the active endopeptidase that cleaves protein substrates on the C-terminal side of asparagine residues. Mice lacking the encoded protein exhibit defects in the lysosomal processing of proteins resulting in their accumulation in the lysosomes, and develop symptoms resembling hemophagocytic lymphohistiocytosis.

Legumain is a highly specific asparaginyl endopeptidase located in the lysosome. Its precursor zymogen consists of three parts, the signal peptide, the precursor peptide and the active site containing the mature protease. Studies have sequenced mammalian legumain, in which the relative molecular mass of pig Legumain is about 34 x 103, and the relative molecular mass after deglycosylation is 31 X103; the coding gene of human Legumain is located on human chromosome 14q32. The relative molecular mass is 49x103, which consists of 433 amino acid residues. After deglycosylation, the relative molecular mass of mature Legumain with bioactivity is 31 x103; the relative molecular mass of mouse Legumain is 35x10%. Under normal conditions, Legumain is not expressed or only expressed at low levels in mammals, only activated under acidic conditions (pH = 3 to 6), and becomes unstable when pH> 6.
Asparagine endopeptidase (LGUM) is a new member of the cysteine protease family. It was first discovered in plant beans and cowpeas, and the researchers later found that legumain is expressed in vertebrates and mammals. Like other cathepsins, legumain is mainly localized in the lysosomes of cells and involved in the degradation of various physiological processes such as matrix proteins.
Studies have shown that the legumain gene is highly expressed in a variety of tumor tissues, and the high expression of legumain is closely related to the tumor development and tumor invasion and metastasis. As a newly discovered protease closely related to tumor invasion and metastasis, Legumain plays an important role in tumor cells and tumor microenvironment, further elucidating the role and mechanism of Legumain in tumor growth and metastasis and the regulation mechanism of Legumain expression. It can provide new targets for the diagnosis, treatment and prevention of malignant tumors.