The regulated loss of plasma membrane phosphatidylserine (PS) asymmetry is critical to
many biological processes. In particular, the appearance of PS at the cell surface, a hallmark
of apoptosis, prepares the dying cell for engulfment and elimination by phagocytes. While it
is well established that PS externalization is regulated by activation of a calcium-dependent
phospholipid scramblase activity in concert with inactivation of the aminophospholipid
translocase, there is no evidence indicating that these processes are triggered and …