Human LILRB4 (ILT-3) knockout A549 cell lysate

Supplementary information

This supplementary information is collated from multiple sources and compiled automatically.

ILT-3 also known as Immunoglobulin-like transcript 3 is a protein predominantly expressed on dendritic cells and monocytes. It is a type I transmembrane protein belonging to the leukocyte immunoglobulin-like receptor family. The ILT-3 protein has a molecular mass of approximately 60 kDa. In addition to its presence on dendritic cells and monocytes ILT-3 can be detected in low levels on some types of macrophages. It plays a regulatory role in the immune system which can influence how the body responds to pathogens and tissue damage.

Biological function summary

ILT-3 acts as an inhibitory receptor that modulates immune responses. It is often linked with the control of T cell activation and the maintenance of immune tolerance. ILT-3 does not form part of a larger protein complex. Its inhibitory function helps in preventing overactivation of the immune system by modulating the signaling pathways necessary for immune response. This modulation occurs through ITIM (Immunoreceptor Tyrosine-based Inhibitory Motif) domains that recruit phosphatases helping in dephosphorylating key signaling proteins and aiding in downregulation of immune cell activities.

Pathways

The ILT-3 protein is involved in important immune regulatory pathways contributing significantly to the immune checkpoint pathway. It interacts with other immunoglobulin-like receptors and is known to influence pathways involving PD-1 (Programmed cell death protein 1) and CTLA-4 (Cytotoxic T-lymphocyte-associated protein 4). By affecting these pathways ILT-3 serves as a checkpoint that ensures immune homeostasis prevents excess inflammation and influences the balance between immune activation and suppression within the body.

ILT-3 has been implicated in autoimmune diseases and transplant rejection. It helps in suppressing immune responses that can lead to conditions like rheumatoid arthritis and could negatively affect organ transplant outcomes by minimizing the chance of rejection. ILT-3's role in these conditions connects it to proteins such as HLA-G and PD-L1 which are also involved in immune modulation and contribute to disease pathogenesis. Understanding ILT-3’s role provides insights into potential therapeutic targets for these diseases.