Biomaterial Database

Erythrocyte membrane vesicles and irreversibly sickled cells bind protein S. 1994

P A Lane, and J L O'Connell, and R A Marlar

Colorado Sickle Cell Treatment and Research Center, University of Colorado School of Medicine, Denver.

Plasma levels of free protein S, a vitamin K-dependent anticoagulant, are decreased in persons with sickle cell anemia, but the etiology of the low levels is unknown. Protein S binds to phosphatidylserine-containing phospholipids in a calcium-dependent manner. Other studies have indicated that phosphatidylserine may be abnormally present on the outer surface of the membrane lipid bilayer of sickle cells and of the spectrin-depleted vesicles they shed in vivo. We studied the binding of purified, radiolabeled protein S to spectrin-depleted erythrocyte membrane vesicles and to density-separated fractions of sickle and normal erythrocytes. Calcium-dependent binding of protein S occurred with vesicles and with well-aerated dense irreversibly sickled cells, but not with well-aerated sickle discocytes or with normal erythrocytes. These data provide further evidence that phosphatidylserine is abnormally present on the outer surface of spectrin-depleted vesicles and of irreversibly sickled cells. In addition, protein S binding to such sickle membranes in vivo may be responsible, in part, for the decreased levels of free protein S in sickle cell plasma.

UI	MeSH Term	Description	Entries
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D011516	Prothrombin	A plasma protein that is the inactive precursor of thrombin. It is converted to thrombin by a prothrombin activator complex consisting of factor Xa, factor V, phospholipid, and calcium ions. Deficiency of prothrombin leads to hypoprothrombinemia.	Coagulation Factor II,Factor II,Blood Coagulation Factor II,Differentiation Reversal Factor,Factor II, Coagulation,Factor, Differentiation Reversal,II, Coagulation Factor
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002474	Cell-Free System	A fractionated cell extract that maintains a biological function. A subcellular fraction isolated by ultracentrifugation or other separation techniques must first be isolated so that a process can be studied free from all of the complex side reactions that occur in a cell. The cell-free system is therefore widely used in cell biology. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p166)	Cellfree System,Cell Free System,Cell-Free Systems,Cellfree Systems,System, Cell-Free,System, Cellfree,Systems, Cell-Free,Systems, Cellfree
D004910	Erythrocyte Membrane	The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.	Erythrocyte Ghost,Red Cell Cytoskeleton,Red Cell Ghost,Erythrocyte Cytoskeleton,Cytoskeleton, Erythrocyte,Cytoskeleton, Red Cell,Erythrocyte Cytoskeletons,Erythrocyte Ghosts,Erythrocyte Membranes,Ghost, Erythrocyte,Ghost, Red Cell,Membrane, Erythrocyte,Red Cell Cytoskeletons,Red Cell Ghosts
D004913	Erythrocytes, Abnormal	Oxygen-carrying RED BLOOD CELLS in mammalian blood that are abnormal in structure or function.	Abnormal Erythrocytes,Abnormal Erythrocyte,Erythrocyte, Abnormal
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000755	Anemia, Sickle Cell	A disease characterized by chronic hemolytic anemia, episodic painful crises, and pathologic involvement of many organs. It is the clinical expression of homozygosity for hemoglobin S.	Hemoglobin S Disease,HbS Disease,Sickle Cell Anemia,Sickle Cell Disease,Sickle Cell Disorders,Sickling Disorder Due to Hemoglobin S,Anemias, Sickle Cell,Cell Disease, Sickle,Cell Diseases, Sickle,Cell Disorder, Sickle,Cell Disorders, Sickle,Disease, Hemoglobin S,Hemoglobin S Diseases,Sickle Cell Anemias,Sickle Cell Diseases,Sickle Cell Disorder
D013049	Spectrin	A high molecular weight (220-250 kDa) water-soluble protein which can be extracted from erythrocyte ghosts in low ionic strength buffers. The protein contains no lipids or carbohydrates, is the predominant species of peripheral erythrocyte membrane proteins, and exists as a fibrous coating on the inner, cytoplasmic surface of the membrane.	alpha-Spectrin,beta-Spectrin,alpha Spectrin,beta Spectrin
D017293	Protein S	The vitamin K-dependent cofactor of activated PROTEIN C. Together with protein C, it inhibits the action of factors VIIIa and Va. A deficiency in protein S; (PROTEIN S DEFICIENCY); can lead to recurrent venous and arterial thrombosis.	Vitamin K-Dependent Protein S,Cofactor Protein S,Protein S, Vitamin K-Dependent,Protein S, Cofactor,Protein S, Vitamin K Dependent,Vitamin K Dependent Protein S