Inhibition of protein cross-linking in calcium-enriched human erythrocytes and activated platelets

Abstract

Treatment of human erythrocytes with Ca2+, in the presence of ionophore A23187, causes the formation of high molecular weight (greater than 10(6)) membrane protein polymers. This phenomenon, known to involve cross-linking of essentially all of the band 4.1 and 2.1 (ankyrin) proteins, as well as some spectrin, band 3, and hemoglobin molecules, could be prevented by preincubating the cells with a noncompetitive inhibitor of intrinsic transglutaminase, 2-[3-(diallylamino)propionyl]benzothiophene, at concentrations of about (3-6) X 10(-4) M. The compound also eliminated the proteolytic breakdown of the two major transmembrane proteins band 3 and glycophorin, which would otherwise occur during the Ca2+ loading of fresh human red cells. In addition, the inhibitor effectively blocked the formation of a cross-linked protein polymer in thrombin-activated human platelets.

Enhancement of platelet reactivity and modulation of eicosanoid production by intact erythrocytes. A new approach to platelet activation and recruitment.

“…This suggested that the releasable pool of EPA was not "metabolically exhausted." Alternatively, ionophore could have acted on erythrocytes (17,18), as well as platelets, thereby initiating eicosanoid metabolism in this cellcell interaction via different mechanisms than collagen or thrombin.…”

Transglutaminases and Disease: Lessons From Genetically Engineered Mouse Models and Inherited Disorders

“…TG2-mediated cross-linking can be uncoupled from proteolysis by differential inhibitors (165), or by a few days of blood bank storage, which greatly diminishes Ca 2ϩ -induced proteolysis without impairing TG2-catalyzed modification of membrane skeleton (171).…”

Transglutaminase Function in Epidermis

“…Several members of this family have been characterized (Phillips et al, 1990;Kim et al, 1991;Aeschlimann et al, 1998;Grenard et al, 2001) (Table II). These include Factor XIIIa, which is involved in stabilization of fibrin clots and in wound healing (Siefring Jr et al, 1978;Lorand and Graham, 2003), TGase 4, which is involved in the cross-linking of seminal fluid (Dubbink et al, 1998), Band 4.2, an inactive TGase, which is a structural protein in erythroblasts and erythrocytes (Lorand et al, 1987), TGase 2, a ubiquitously expressed TGase with multiple functions (Fesus and Piacentini, 2002;Griffin et al, 2002), and the epidermal-specific TGase, TGase 1 (Phillips et al, 1990;Polakowska et al, 1991), TGase 3 (Kim et al, 1994a), and TGase 5 (Candi et al, 2001(Candi et al, , 2002(Candi et al, , 2004Grenard et al, 2001). Four TGase family members are expressed in keratinocytes and/or in epidermal tissues-TGase 1, TGase 2, TGase 3, and TGase 5 (Table III).…”