Leucine-rich repeat-containing protein 25(LRRC25) is a single-pass type I membrane protein and contains 3 LRR (leucine-rich) repeats. The protein expressed in plasmacytoid dendritic cells (PDC), monocyte-derived dendritic cells (MDDC), granulocytes, monocytes, B-lymphocytes, peripheral blood leukocytes, spleen, bone marrow, and, to a lesser extent, lymph nodes, fetal liver, and appendix but not in thymus. The protein may be involved in the activation of cells of innate and acquired immunity.