Proteomics of Galápagos Marine Iguanas Links Function of Femoral Gland Proteins to the Immune System

Femoral glands secrete a wax-like substance on the inner side of lizard hind legs, which is thought to function as a mode of chemical communication. Though the minor volatile fraction is well studied, the major protein fraction remains enigmatic. Here, we use proteomics to analyze proteins in femoral gland secretions of the Galápagos marine iguana. Although we found no evidence for proteins and peptides involved in chemical communication, we found several immune-regulatory proteins which also demonstrate anti-microbial functions. Accordingly, we show that femoral gland proteins and peptides function as a barrier against microbial infection and may prevent the rapid degradation of volatile s…