LIX1 (protein limb expression 1 homolog), also known as C5orf11, is a 282 amino acid protein belonging to the LIX1 family. Other members of the LIX1 family include LIX1L (LIX1-like protein). Although the function of LIX1 is unknown, the predicted secondary structure is compatible with a role in RNA metabolism. The C-terminal 100 amino acids of LIX1 also have a 98% probability of forming a coiled-coil structure. Therefore, LIX1 may interact with the many coiled-coil proteins found in most cells. LIX1 expression is largely restricted to the central nervous system, primarily in spinal motor neurons. The gene encoding LIX1 maps to human chromosome 5q15 and mouse chromosome 17 A3.2.