Another unique identifying feature that differs between the various classes of endosomes is the lipid composition in their membranes. Phosphatidyl inositol phosphates (PIPs), one of the most important lipid signaling molecules, is found to differ as the endosomes mature from early to late. PI(4,5)P2 is present on plasma membranes, PI(3)P on early endosomes, PI(3,5)P2 on late endosomes and PI(4)P on the trans Golgi network. These lipids on the surface of the endosomes help in the specific recruitment of proteins from the cytosol, thus providing them an identity. The inter-conversion of these lipids is a result of the concerted action of phosphoinositide kinases and phosphatases that are strategically localized