Abstract

Triflavin, an Arg-Gly-Asp (RGD)-containing disintegrin purified from venom peptide inhibited platelet aggregation by interfering with the interaction of fibrinogen with αIIbβ3 integrin. Using an immunostaining technique and electron microscopy, we investigated and compared the distribution of triflavin binding in both resting and activated platelets. Triflavin uniformly and strongly stained the plasma membrane and the open canalicular system (OCS), whereas a lesser extent of staining was seen on α-granules in both resting and activated platelets. Furthermore, resting unfixed platelets were incubated with triflavin for 10 min at 4°C, and then rewarmed at 30°C for 0, 10, and 30 min to advance internalization. At 0 min, platelets showed an extensive rim-staining pattern of bound triflavin on the surface membrane, which was then gradually internalized into the cytoplasmic OCS with prolonging of incubation times. However, triflavin bound fewer to α-granules than to the OCS within the 0-30-min period of internalization in both resting and activated platelets. Furthermore, triflavin did not influence physiological endocytosis in resting platelets. Comparing the 3D structures of triflavin and another disintegrin, echistatin, we found that the spatial differences between the RGD motif and the C-termini of structures of disintegrins may mediate functional differences of binding activity towards αIIbβ3 integrin in resting platelets. These data indicate that (1) triflavin binds effectively to αIIbβ3 on the platelet membrane and cytoplasmic OCS, but a relative lesser extent to α-granules in both resting and activated platelets; (2) triflavin is internalized in resting platelets independent of cellular activation; and (3) spatial differences between the RGD motif and the C-termini of disintegrins may play an important role in mediating disintegrin binding to αIIbβ3 in resting platelets.

Original languageEnglish
Pages (from-to)37-46
Number of pages10
JournalThrombosis Research
Volume109
Issue number1
DOIs
Publication statusPublished - Jan 1 2003

Fingerprint

Integrins
Electron Microscopy
Blood Platelets
Disintegrins
triflavin
Cell Membrane
Staining and Labeling
Venoms
Endocytosis
Platelet Aggregation
Fibrinogen
Peptides
Membranes

Keywords

  • αβ integrin
  • 3D structure
  • Internalization
  • Platelet
  • Triflavin

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Hematology

Cite this

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title = "Comparison of the binding character of triflavin on resting and activated αIIbβ3 integrin in human platelets by electron microscopy",
abstract = "Triflavin, an Arg-Gly-Asp (RGD)-containing disintegrin purified from venom peptide inhibited platelet aggregation by interfering with the interaction of fibrinogen with αIIbβ3 integrin. Using an immunostaining technique and electron microscopy, we investigated and compared the distribution of triflavin binding in both resting and activated platelets. Triflavin uniformly and strongly stained the plasma membrane and the open canalicular system (OCS), whereas a lesser extent of staining was seen on α-granules in both resting and activated platelets. Furthermore, resting unfixed platelets were incubated with triflavin for 10 min at 4°C, and then rewarmed at 30°C for 0, 10, and 30 min to advance internalization. At 0 min, platelets showed an extensive rim-staining pattern of bound triflavin on the surface membrane, which was then gradually internalized into the cytoplasmic OCS with prolonging of incubation times. However, triflavin bound fewer to α-granules than to the OCS within the 0-30-min period of internalization in both resting and activated platelets. Furthermore, triflavin did not influence physiological endocytosis in resting platelets. Comparing the 3D structures of triflavin and another disintegrin, echistatin, we found that the spatial differences between the RGD motif and the C-termini of structures of disintegrins may mediate functional differences of binding activity towards αIIbβ3 integrin in resting platelets. These data indicate that (1) triflavin binds effectively to αIIbβ3 on the platelet membrane and cytoplasmic OCS, but a relative lesser extent to α-granules in both resting and activated platelets; (2) triflavin is internalized in resting platelets independent of cellular activation; and (3) spatial differences between the RGD motif and the C-termini of disintegrins may play an important role in mediating disintegrin binding to αIIbβ3 in resting platelets.",
keywords = "αβ integrin, 3D structure, Internalization, Platelet, Triflavin",
author = "Chuang, {Woei Jer} and Wu, {Ching Hsiang} and Huang, {He Nan} and Chen, {Seu Hwa} and George Hsiao and Chien-Huang Lin and Sheu, {Joen Rong}",
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T1 - Comparison of the binding character of triflavin on resting and activated αIIbβ3 integrin in human platelets by electron microscopy

AU - Chuang, Woei Jer

AU - Wu, Ching Hsiang

AU - Huang, He Nan

AU - Chen, Seu Hwa

AU - Hsiao, George

AU - Lin, Chien-Huang

AU - Sheu, Joen Rong

PY - 2003/1/1

Y1 - 2003/1/1

N2 - Triflavin, an Arg-Gly-Asp (RGD)-containing disintegrin purified from venom peptide inhibited platelet aggregation by interfering with the interaction of fibrinogen with αIIbβ3 integrin. Using an immunostaining technique and electron microscopy, we investigated and compared the distribution of triflavin binding in both resting and activated platelets. Triflavin uniformly and strongly stained the plasma membrane and the open canalicular system (OCS), whereas a lesser extent of staining was seen on α-granules in both resting and activated platelets. Furthermore, resting unfixed platelets were incubated with triflavin for 10 min at 4°C, and then rewarmed at 30°C for 0, 10, and 30 min to advance internalization. At 0 min, platelets showed an extensive rim-staining pattern of bound triflavin on the surface membrane, which was then gradually internalized into the cytoplasmic OCS with prolonging of incubation times. However, triflavin bound fewer to α-granules than to the OCS within the 0-30-min period of internalization in both resting and activated platelets. Furthermore, triflavin did not influence physiological endocytosis in resting platelets. Comparing the 3D structures of triflavin and another disintegrin, echistatin, we found that the spatial differences between the RGD motif and the C-termini of structures of disintegrins may mediate functional differences of binding activity towards αIIbβ3 integrin in resting platelets. These data indicate that (1) triflavin binds effectively to αIIbβ3 on the platelet membrane and cytoplasmic OCS, but a relative lesser extent to α-granules in both resting and activated platelets; (2) triflavin is internalized in resting platelets independent of cellular activation; and (3) spatial differences between the RGD motif and the C-termini of disintegrins may play an important role in mediating disintegrin binding to αIIbβ3 in resting platelets.

AB - Triflavin, an Arg-Gly-Asp (RGD)-containing disintegrin purified from venom peptide inhibited platelet aggregation by interfering with the interaction of fibrinogen with αIIbβ3 integrin. Using an immunostaining technique and electron microscopy, we investigated and compared the distribution of triflavin binding in both resting and activated platelets. Triflavin uniformly and strongly stained the plasma membrane and the open canalicular system (OCS), whereas a lesser extent of staining was seen on α-granules in both resting and activated platelets. Furthermore, resting unfixed platelets were incubated with triflavin for 10 min at 4°C, and then rewarmed at 30°C for 0, 10, and 30 min to advance internalization. At 0 min, platelets showed an extensive rim-staining pattern of bound triflavin on the surface membrane, which was then gradually internalized into the cytoplasmic OCS with prolonging of incubation times. However, triflavin bound fewer to α-granules than to the OCS within the 0-30-min period of internalization in both resting and activated platelets. Furthermore, triflavin did not influence physiological endocytosis in resting platelets. Comparing the 3D structures of triflavin and another disintegrin, echistatin, we found that the spatial differences between the RGD motif and the C-termini of structures of disintegrins may mediate functional differences of binding activity towards αIIbβ3 integrin in resting platelets. These data indicate that (1) triflavin binds effectively to αIIbβ3 on the platelet membrane and cytoplasmic OCS, but a relative lesser extent to α-granules in both resting and activated platelets; (2) triflavin is internalized in resting platelets independent of cellular activation; and (3) spatial differences between the RGD motif and the C-termini of disintegrins may play an important role in mediating disintegrin binding to αIIbβ3 in resting platelets.

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KW - 3D structure

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