Evidence that activation of platelet calpain is induced as a consequence of binding of adhesive ligand to the integrin, glycoprotein IIb-IIIa.

Fox, Joan E.B.; Taylor, Richard G.; Taffarel, M; Boyles, J K; Goll, Darrel E.

doi:10.1083/jcb.120.6.1501

Cited by 140 publications

(134 citation statements)

References 44 publications

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“…8), established that this peptide is cleaved at a site identical to that of the native αII spectrin heterotetramer (Table I). Calpain did not appreciably digest peptides GST-αII [13][14][15][16][17][18] and GST-αII 18-C (data not shown). Calpain digestion of GST-βII 8-CΔ , a fusion peptide encompassing βII spectrin repeat units 8 to 17 and a portion of domain III (58), yielded four cleavage fragments at ≈ 92, ≈ 88, ≈ 70, and ≈ 47 kD (Figure 3).…”

Section: Recombinant Spectrin Peptides Are Cleaved By Calpain At the mentioning

confidence: 91%

Sequential Degradation of αII and βII Spectrin by Calpain in Glutamate or Maitotoxin-Stimulated Cells

et al. 2006

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Calpain-catalyzed proteolysis of αII-spectrin is a regulated event associated with neuronal long-term potentiation, platelet and leukocyte activation, and other processes. Calpain proteolysis is also linked to apoptotic and non-apoptotic cell death following excessive glutamate exposure, hypoxia, HIVgp120/160 exposure, or toxic injury. The molecular basis for these divergent consequences of calpain action, and their relationship to spectrin proteolysis, is unclear. Calpain preferentially cleaves αII spectrin in vitro in repeat 11 between residues Y 1176 and G 1177 . Unless stimulated by Ca ++ and calmodulin (CaM), βII spectrin proteolysis in vitro is much slower. We identify additional unrecognized sites in spectrin targeted by calpain in vitro and in vivo. Bound CaM induces a second αII spectrin cleavage at G 1230 *S 1231 . βII spectrin is cleaved at four sites. One cleavage only occurs in the absence of CaM at high enzyme-to-substrate ratios near the βII spectrin COOH-terminus. CaM promotes βII spectrin cleavages at Q1440*S1441, S1447*Q1448, and L1482*A1483. These sites are also cleaved in the absence of CaM in recombinant βII spectrin fusion peptides, indicating that they are probably shielded in the spectrin heterotetramer and become exposed only after CaM binds αII spectrin. Using epitope-specific antibodies prepared to the calpain cleavage sites in both αII and βII spectrin, we find in cultured rat cortical neurons that brief glutamate exposure (a physiologic ligand) rapidly stimulates αII spectrin cleavage only at Y 1176 *G 1177 , while βII spectrin remains intact. In cultured SH-SY5Y cells that lack an NMDA receptor, glutamate is without effect. Conversely, when stimulated by calcium influx (via maitotoxin), there is rapid and sequential cleavage of αII and then βII spectrin, coinciding with the onset of non-apoptotic cell death. These results identify: i) novel calpain target sites in both αII and βII spectrin; ii) trans-regulation of proteolytic susceptibility between the spectrin subunits in vivo; and iii) the preferential cleavage of αII spectrin vs. βII spectrin when responsive cells are stimulated by engagement of the NMDA receptor. We postulate that calpain proteolysis of spectrin can activate two physiologically distinct responses: one that enhances skeletal plasticity without destroying the spectrin-actin skeleton, characterized by preservation of βII spectrin; or an alternative response closely correlated with nonapoptotic cell death and characterized by proteolysis of βII spectrin and complete dissolution of the spectrin skeleton. Spectrin is the major component of the cytoskeletal network associated with the plasma membrane of vertebrate cells (for reviews 1 , 2 , 3). While seven spectrin genes exist, encoding two variants of an alpha spectrin and five beta spectrins, the most common form of this protein is a heterotetramer of αII,βII spectrin. Together with actin and a host of adapter proteins, spectrin controls the distribution of many integral and peripheral membrane proteins, and ...

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Section: Recombinant Spectrin Peptides Are Cleaved By Calpain At the mentioning

confidence: 91%

Sequential Degradation of αII and βII Spectrin by Calpain in Glutamate or Maitotoxin-Stimulated Cells

et al. 2006

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“…Association of PMCA with the Platelet Membrane Cytoskeleton-Most of the cytoplasmic actin filaments in unstimulated platelets are aggregated into large complexes that sediment from TX100-lysed platelets at 16,000 ϫ g (low speed pellet) (19). However, the membrane-associated skeletal fragments and associated proteins such as integrin ␣ IIb ␤ 3 , spectrin, vinculin, and p60src require 100,000 ϫ g for sedimentation from TX100-lysed unstimulated platelets (high speed pellet) (20).…”

Section: Resultsmentioning

confidence: 99%

“…Thus it is the more active, less phosphorylated form that associates with the cytoplasmic cytoskeleton. This implies that the purpose of redistribution of PMCA is to direct the active Ca 2ϩ pump to specific locations in the activated platelet, possibly to reduce intracellular Ca 2ϩ in focal contact regions thus preventing proteolytic degradation by the Ca 2ϩ -activated proteinase calpain (19). The concomitant inhibition of the pump not associated with the cytoskeleton by tyrosine phos- FIG.…”

Section: Plasma Membrane Ca 2ϩ -Atpase Binding To Platelet Cytoskeletonmentioning

confidence: 99%

Plasma Membrane Ca2+-ATPase Associates with the Cytoskeleton in Activated Platelets through a PDZ-binding Domain

Zabe

Dean

2001

Journal of Biological Chemistry

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The plasma membrane Ca 2؉ -ATPase (PMCA) plays an essential role in maintaining low cytosolic Ca 2؉ in resting platelets. During platelet activation PMCA is phosphorylated transiently on tyrosine residues resulting in inhibition of the pump that enhances elevation of Ca 2؉ . Tyrosine phosphorylation of many proteins during platelet activation results in their association with the cytoskeleton. Consequently, in the present study we asked if PMCA interacts with the platelet cytoskeleton. We observed that very little PMCA is associated with the cytoskeleton in resting platelets but that ϳ80% of total PMCA (PMCA1b ؉ PMCA4b) is redistributed to the cytoskeleton upon activation with thrombin. Tyrosine phosphorylation of PMCA during activation was not associated with the redistribution because tyrosine-phosphorylated PMCA was not translocated specifically to the cytoskeleton. Because PMCA b-splice isoforms have C-terminal PSD-95/Dlg/ZO-1 homology domain (PDZ)-binding domains, a C-terminal peptide was used to disrupt potential PDZ domain interactions. Activation of saponin-permeabilized platelets in the presence of the peptide led to a significant decrease of PMCA in the cytoskeleton. PMCA associated with the cytoskeleton retained Ca 2؉ -ATPase activity. These results suggest that during activation active PMCA is recruited to the cytoskeleton by interaction with PDZ domains and that this association provides a microenvironment with a reduced Ca 2؉ concentration.

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“…Work on platelets has shown that the cysteine protease, calpain, is one of the signaling molecules activated following integrin-ligand interactions (35), suggesting it may modulate intracellular events required for effective adhesion. Once activated, calpain can selectively cleave a variety of substrates, many of which are membrane and cytoskeletal proteins.…”

Section: Discussionmentioning

confidence: 99%

Inhibition of Calpain Is a Component of Nitric Oxide-Induced Down-Regulation of Human Mast Cell Adhesion

Forsythe

Befus

2003

The Journal of Immunology

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Nitric oxide is an important messenger that regulates mast cell activity by modifications to gene expression and intracellular pathways associated with exocytosis and adhesion. Integrin interactions with extracellular matrix components modulate an array of cell activities, including mediator production and secretion. To investigate the molecular mechanisms underlying NO regulation of mast cell function, we studied its effects on adhesion of a human mast cell line (HMC-1) to fibronectin (FN). The NO donors S-nitrosoglutathione and S-nitroso-N-acetylpenicillamine strongly down-regulated the adhesion of HMC-1 to FN. Inhibitors of soluble guanylate cyclase and protein kinase G did not alter the response of cells to NO. A peroxynitrite scavenger did not affect modulation of adhesion by NO, nor could the effect of NO be mimicked by the peroxynitrite-producing compound 3-morpholinosydnonimine. NO donors inhibited the cysteine protease, calpain, while calpain inhibitors mimicked the effect of NO and led to a decrease in the ability of HMC-1 cells to adhere to FN. Thus, NO is an effective down-regulator of human mast cell adhesion. The mechanism for this action does not involve peroxynitrite or activation of soluble guanylate cyclase. Instead, a portion of NO-induced down-regulation of adhesion may be attributed to inhibition of the cysteine protease, calpain, an enzyme that has been associated with control of integrin activation in other cell types. The inhibition of calpain is most likely mediated via nitrosylation of its active site thiol group. Calpain may represent a novel therapeutic target for the regulation of mast cell activity in inflammatory disorders.

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Evidence that activation of platelet calpain is induced as a consequence of binding of adhesive ligand to the integrin, glycoprotein IIb-IIIa.

Cited by 140 publications

References 44 publications

Sequential Degradation of αII and βII Spectrin by Calpain in Glutamate or Maitotoxin-Stimulated Cells

Sequential Degradation of αII and βII Spectrin by Calpain in Glutamate or Maitotoxin-Stimulated Cells

Plasma Membrane Ca2+-ATPase Associates with the Cytoskeleton in Activated Platelets through a PDZ-binding Domain

Inhibition of Calpain Is a Component of Nitric Oxide-Induced Down-Regulation of Human Mast Cell Adhesion

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