pSIVA REAL-TIME Apoptosis Fluorescent Microscopy Kit

The process of apoptosis is undertaken in several stages defined by specific cellular morphologies. One of the earlier stages of apoptosis is a change of the plasma membrane’s phospholipid asymmetry. This rearrangement results in the translocation of phosphatidylserine (PS) from the inner to the outer plasma membrane (in non-apoptotic cells PS is exclusively located to the inner plasma membrane). However, apoptosis is reversible until reaching a certain point in the pathway and until then PS exposure can be considered as a transient event. The event defining whether the cell can be rescued and continues living is the onset of mitochondrial outer membrane permeabilization (Chipuk et al. 2006). Prior to reaching this point, PS exposure may be transient as molecules can relocate back to the inner plasma membrane (a phenomenon known as “PS flipping”) (van der Mark et al. 2013).The pSIVA™ (polarity-Sensitive Indicator of Viability & Apoptosis) probe is a biosensor conjugated to the green emitting IANBD dye (excitation maximum 488 nm, emission maximum 530 nm) and only fluoresces when bound to PS in the presence of Ca²⁺ (Kim et al. 2010a, 2010b). The method thereby allows the analysis of kinetic apoptosis events in real time by live cell imaging and immunofluorescence / immunocytochemistry. In contrast to other PS detection based assays (e.g. annexin V) the pSIVA^TM Real-Time Apoptosis Fluorescent Microscopy Kit does not require washing steps as you can simply add the probe and start analyzing.