Leucine-rich repeat-containing protein 31 (LRRC31)

Leucine-rich repeat-containing protein 31 (LRRC31) is a nuclear protein characterized by multiple leucine-rich repeat motifs, forming a horseshoe-like structure that mediates protein-protein interactions essential for DNA damage response. LRRC31 specifically inhibits non-homologous end joining (NHEJ) DNA double-strand break repair through direct interaction with ATR and Ku70/Ku80 complex, impacting the recruitment and activation of DNA-PKcs and interfering with the MSH2-ATR signaling module. In epithelial tissues, LRRC31 is induced by IL-13 and enhances epithelial barrier function, in part by downregulating multiple kallikrein-related serine proteases (KLKs). LRRC31 is implicated in human diseases including cancer (as a tumor suppressor and radiosensitizing factor in breast cancer brain metastasis) and inflammatory disorders like eosinophilic esophagitis (where it may serve as an early biomarker of response to therapy)[1][3].

Other names

LRRC31UNQ9367/PRO34156FLJ23259HEL-S-293Epididymis secretory protein Li 293Epididymis secretory sperm binding protein

As a radiosensitizing gene, modulation of LRRC31 inhibits DNA repair protein recruitment and disrupts downstream signaling pathways (e.g., ATR-MSH2 complex) leading to increased radiosensitivity of cancer cells[1].