Cell membranes are incredibly crowded environments packed with proteins, lipids and carbohydrates. Competition for space is fierce and membrane proteins have to contend with many other molecules, as well as macromolecular structures from within, above and below the phospholipid bilayer. Metavitropic glutamate receptors are class C, G-protein coupled receptor membrane proteins, or GPCRs, as they are commonly known. They have an extracellular domain with ligand binding regions, and a transmembrane domain with intracellular C-termini. Previously, it was believed that membrane proteins, such as GPCRs, will, more often than not, exhibit random brownie emotion when diffusing laterally across the membrane, as pictured here. We now know that this is seldom the case, due to frequent interactions with other proteins, lipids, as well as larger macromolecular structures and organelles. In fact, GPCRs can exhibit as many as four different modes of diffusion, where mobility can be influenced by interactions with other molecules and structures either above, within, or beneath the cell membrane. Yanagawa et al observed that metavitropic glutamate receptor-free, pre-coupled with G-proteins, will diffuse rapidly across the membrane, exhibiting either brownie or directed motion. After the GPCR molecule transitions from fast to much lower displacement, confinement can be observed. This takes place within fences or corrals, principally formed by the intracellular actin-based cytoskeleton, but also with a high degree of molecular crowding, including an increased concentration of cholesterol. Agonis binding promotes a conformational change in the GPCR, from the resting to the active state. In the active state, Englua is more likely to exhibit confinement within cytoskeletal fences, which form a hot spot for G-protein activation. The activated G-protein dissociates into its alpha and beta-gammer subunits. Still within the actin cytoskeletal fences, the C-terminus of the GPCR becomes phosphorylated by G-protein-coupled receptor kinases. C-terminal phosphorylation acts as a signal for the recruitment of a rest in to the metavitropic glutamate receptor. A rest in binding causes the GPCR to become immobilized within a claffer-encoded pit, where the diffusion mode transitions from confinement to restriction. After immobilization, the GPCR is endocytosed into the cell within claffer-encoded vesicles, where it can be degraded or recycled for future use. In the active state, the C-terminus of the GPCR is the most likely to be degraded. The C-terminus of the GPCR is the most likely to be degraded. The C-terminus of the GPCR is the most likely to be degraded. The C-terminus of the GPCR is the most likely to be degraded. The C-terminus of the GPCR is the most likely to be degraded.