The Receptor Site for Amphotericin B
by Isabella Lombardo
Every fungus cell has a plasma membrane and every plasma membrane has a phospholipid bilayer structure with many proteins, lipids, and sterols embedded in it.   The sterol contributes to the membrane’s fluidity and stability as a necessary element of the plasma membrane.  In addition, sterols prevent the fatty acid portions of the membrane (nonpolar hydrophobic tails) from packing together, crystallizing, and drastically reducing the membrane’s fluidity.  Amphotericin B binds to the sterol content of the plasma membrane and fits right in.  The antifungal antibiotic interacts with ergosterol, the major sterol in the plasma membranes of all fungi.  This pseudo-membrane (the Amphotericin B rooted in the ergosterol of the fungus membrane), though has a specific function.  The Amphotericin B forms pores and channels in the fungus membrane allowing essential intracellular materials, like glucose and potassium, to leak out and prevents vital nutrients from getting in and starving the fungus.  Eventually, this leads to cell death.