Jun 24, 2009

Bovine lactadherin as a calcium-independent imaging agent of phosphatidylserine expressed on the surface of apoptotic HeLa cells

The Journal of Histochemistry and Cytochemistry : Official Journal of the Histochemistry Society
Lasse N WaehrensJan T Rasmussen


Bovine lactadherin holds a stereo-specific affinity for phosphatidylserine (PS) membrane domains and binds at PS concentrations lower than the benchmark PS probe, annexin V. Accordingly, lactadherin has recognized PS exposure on preapoptotic immortalized leukemia cells at an earlier time point than has annexin V. In the present study, the cervical cancer cell line HeLa has been employed as a model system to compare the topographic distribution of PS with the two PS binding proteins as adherent cells enter the apoptotic program. HeLa cells were cultured on glass-bottom Petri dishes, and apoptosis was induced by staurosporine. Fluorescence-labeled lactadherin and/or annexin V were used to detect PS exposure by confocal microscopy. Both lactadherin and annexin V staining revealed PS localized to plasma membrane rim and blebs. In addition, lactadherin identified PS exposure on long filopodia-like extensions, whereas annexin V internalized in granule-like structures. All in all, the data further delineate the differences in PS binding patterns of lactadherin and annexin V.

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Mentioned in this Paper

Calcium [EPC]
Annexin A5
Apoptosis, Intrinsic Pathway
PAS-7 glycoprotein, Bos taurus
Bos taurus
ANXA5 gene

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Apoptosis is a specific process that leads to programmed cell death through the activation of an evolutionary conserved intracellular pathway leading to pathognomic cellular changes distinct from cellular necrosis