Answer
PS is a useful marker of a moribund cell because, in normal healthy cells, PS is found confined to the inner leaflet of the plasma membrane and it is only in apoptotic cell or moribund cell that PS is found on the outer surface of the target cell. PS face the cytosolic (inner) side of the cell membrane and are held in that way by the enzyme flippase.But, when a cell undergoes apoptosis, PS is no longer restricted to the cytosolic side,rather, enzyme scramblase functions in the process of catalysis that leads to the rapid exchange of phosphatidylserine between the two sides i.e outer and inner side. When the PS moves to the extracellular (outer) surface of the cell, it acts as a signal for the macrophages to engulf that cell.
Work Step by Step
PS is a useful marker of a moribund cell because, in normal healthy cells, PS is found confined to the inner leaflet of the plasma membrane and it is only in apoptotic cell or moribund cell that PS is found on the outer surface of the target cell. PS face the cytosolic (inner) side of the cell membrane and are held in that way by the enzyme flippase.But, when a cell undergoes apoptosis, PS is no longer restricted to the cytosolic side,rather, enzyme scramblase functions in the process of catalysis that leads to the rapid exchange of phosphatidylserine between the two sides i.e outer and inner side. When the PS moves to the extracellular (outer) surface of the cell, it acts as a signal for the macrophages to engulf that cell.
