22 April 1997, Volume 4, Issue 4, Pages 311 – 316

Original Paper

Phosphatidylserine plasma membrane asymmetry in vivo: a pancellular phenomenon which alters during apoptosis Stefan M. Van den Eijnde1,5, Lenard Boshart1, Chris P.M. Reutelingsperger2, Chris I. De Zeeuw3 & Christl Vermeij-Keers3,4 1Department of Cell Biology and Genetics, Institute of Clinical Genetics, Erasmus University Medical School, Rotterdam, The Netherlands     2Department of Biochemistry, Cardiovascular Research Institute, Limburg State University, The Netherlands     3Department of Anatomy, Erasmus University Medical School, Rotterdam, The Netherlands     4Department of Plastic and Reconstructive Surgery, Erasmus University Medical School, Rotterdam, The Netherlands     5Author for correspondence tel: +31104087303; fax: +31104365780; email: vandeneijnde@ikg.fgg.eur.nl

Keywords

Annexin V;   cell death;   mouse embryo;   phagocytosis;   phospholipids

Abstract

The distribution of phospholipids across the two leaflets of the plasma membrane is important for many cellular processes including phagocytosis and hemostasis. In the present study we investigated the in vivo plasma membrane distribution of the aminophospholipid phosphatidylserine in mouse embryos with a novel technique employing Annexin V, a Ca2+ dependent phosphatidylserine binding protein, conjugated to fluorescein isothiocyanate and biotin. Annexin V directly applied to cryostat sections labeled the plasma membrane of all cells at the interface. In contrast, Annexin V injected intracardially into viable mouse embryos labeled almost exclusively apoptotic cells. These apoptotic cells were visible in all tissues and derived from all germ layers. Our experiments demonstrate that phosphatidylserine is asymmetrically distributed between the two leaflets of the plasma membrane in virtually all cell types in vivo and that this asymmetry is lost early during apoptosis.

Received 20 September, 96l; Revised 16 December, 96; Accepted 21 January, 97 Edited by A.H. Wyllie

^© Macmillan Publishers Ltd 1997