LY96 is involved in binding lipopolysaccharide with TLR 4. It is also known as "MD2". The MD-2 protein appears to associate with toll-like receptor 4 on the cell surface and confers responsiveness to lipopolysaccyaride (LPS), thus providing a link between the receptor and LPS signaling. MD2 did not interact with LY64, but it did appear on cells expressing Toll-like receptor-4 (TLR4). Toll-like receptors, which contain extracellular LRRs and have intracellular regions homologous to the intracellular signaling domain of the interleukin-1 receptor (IL1R), activate nuclear factor kappa-B (NFKB). TLR4 is involved in the response to lipopolysaccharide (LPS) from gram-negative bacteria. Functional analysis showed that expression of MD2 enhanced TLR4-dependent activation of NFKB.