Identification of residues defining phospholipid flippase substrate specificity of type IV P-type ATPases

摘要

The plasma membrane forms a barrier around cells and is comprised of many different types of phospholipid molecules. These phospholipids are organized into a bilayer structure with strikingly different internal (i.e., cytosolic) and external (i.e., extracellular) sides. Proteins called type IV P-type ATPases (P4-ATPases) establish this phospholipid bilayer asymmetry by moving specific phospholipids across the membrane to the cytosolic side (Fig. PI). The underlying mechanism is unclear, however, as most related P-type ATPases transport small ions, known as their "substrate" (1). To determine how P4-ATPases recognize the bulky phospholipid substrate we searched for parts of the protein responsible for substrate preference.