HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Maffey, K. G. Articles by DeBari, V. A. Search for Related Content PubMed PubMed Citation Articles by Maffey, K. G. Articles by DeBari, V. A.

The Influence of Lipid Composition and Divalent Cations on Annexin V Binding to Phospholipid Mixtures

Correspondence to Vincent A. DeBari, PhD, St. Joseph’s Hospital Medical Center, 703 Main Street, Paterson, NJ 07503, USA; tel 973 754 3561; fax 973 754 3555; e-mail debariv{at}sjhmc.org

Annexin V is a 36-kDa protein which, it has been suggested, is a factor in protecting the vascular endothelium from attack by antibodies to other phospholipid-binding proteins. Competition between annexin V and ß₂-glycoprotein I (ß₂GPI) for phospholipid surfaces is complicated by empirical observations regarding alterations in binding to anionic phospholipid, primarily phosphatidylserine. In order to elucidate the effect of phospholipid composition and divalent cations (Ca⁺² and Mg⁺²) on annexin V binding to phospholipid, we used biotinylated annexin V and peroxidase-conjugated avidin D to probe the binding of annexin V to phospholipid-coated wells of polystyrene microtiter plates. Binding of annexin V to anionic phospholipid is Ca⁺²-dependent and, in its absence, annexin V was found to bind most avidly to 100% phosphatidylcholine in a saturable manner, followed by decreasing percentages of phosphatidylcholine. Ca⁺² was found to inhibit phosphatidylcholine binding and promote the binding of phospholipid mixtures containing phosphatidylserine. Phosphatidylserine (100%) did not bind annexin V as strongly as mixtures of 50% and 75% phosphatidylserine. The effect with Ca⁺² suggests saturation of Ca⁺²-binding sites on annexin V, reached under our experimental conditions at approximately 1 mM. Under the same conditions, Mg⁺² slightly enhanced the binding of all of the phospholipid compositions studied. Ca⁺² -dependent binding of annexin V was competitively inhibited by Mg⁺²; 5 mM Mg⁺² reduced binding significantly (p < 0.0001 by ANOVA, p < 0.05 for post hoc test of 5 mM vs 0 mM). These data suggest that the translocation of membrane phospholipid under the dynamics of ion transport in vascular endothelium may alter annexin V binding.

Keywords: Annexin V, phospholipids, ß₂-glycoprotein I, antiphospholipid syndrome

This article has been cited by other articles:

				A. Yaradanakul, T.-M. Wang, V. Lariccia, M.-J. Lin, C. Shen, X. Liu, and D. W. Hilgemann Massive Ca-induced Membrane Fusion and Phospholipid Changes Triggered by Reverse Na/Ca Exchange in BHK Fibroblasts J. Gen. Physiol., June 30, 2008; 132(1): 29 - 50. [Abstract] [Full Text] [PDF]