Annexin V is associated with which of the following?

Annexin V is a calcium-dependent phospholipid binding protein that has a high affinity for the phophatidylserine (PS), a plasma membrane phospholipid. One of the earliest features of apoptosis is the translocation of PS from the inner to the outer leaflet of the plasma membrane, thereby exposing PS to the external environment. Annexin V binds to PS exposed on the cell surface and identifies cells at an earlier stage of apoptosis than assays based on DNA fragmentation. The Annexin V Assay, a classical technique for detecting apoptosis, is the most commonly used method for detecting apoptosis by flow cytometry.