proteins are found in gram negative bacteria, vertebrate cells, and invertebrate cells, and in plants. Lipocalins have been associated with many biological processes, among them immune response, pheromone transport, biological prostaglandin synthesis, retinoid binding, and cancer cell interactions. Contents 1 Function 1.1 Immune response 1.2 Pheromone transport 1.3 Prostaglandin synthesis 1.4