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Binding of CIB1 to the α(IIb) tail of α(IIb)β(3) is required for FAK recruitment and activation in platelets
BACKGROUND: It is believed that activation of c-Src bound to the integrin β(3) subunit initiates outside-in signaling. The involvement of α(IIb) in outside-in signaling is poorly understood. OBJECTIVES: We have previously shown that CIB1 specifically interacts with the cytoplasmic domain of α(IIb) a...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5443481/ https://www.ncbi.nlm.nih.gov/pubmed/28542214 http://dx.doi.org/10.1371/journal.pone.0176602 |
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author | Naik, Meghna U. Naik, Tejal U. Summer, Ross Naik, Ulhas P. |
author_facet | Naik, Meghna U. Naik, Tejal U. Summer, Ross Naik, Ulhas P. |
author_sort | Naik, Meghna U. |
collection | PubMed |
description | BACKGROUND: It is believed that activation of c-Src bound to the integrin β(3) subunit initiates outside-in signaling. The involvement of α(IIb) in outside-in signaling is poorly understood. OBJECTIVES: We have previously shown that CIB1 specifically interacts with the cytoplasmic domain of α(IIb) and is required for α(IIb)β(3) outside-in signaling. Here we evaluated the role of CIB1 in regulating outside-in signaling in the absence of inside-out signaling. METHODS: We used α(IIb) cytoplasmic domain peptide and CIB1-function blocking antibody to inhibit interaction of CIB1 with α(IIb) subunit as well as Cib1(-/-) platelets to evaluate the consequence of CIB1 interaction with α(IIb) on outside-in signaling. RESULTS: Fibrinogen binding to α(IIb)β(3) results in calcium-dependent interaction of CIB1 with α(IIb), which is not required for filopodia formation. Dynamic rearrangement of cytoskeleton results in CIB1-dependent recruitment of FAK to the α(IIb) complex and its activation. Disruption of the association of CIB1 and α(IIb) by incorporation of α(IIb) peptide or anti-CIB1 inhibited both FAK association and activation. Furthermore, FAK recruitment to the integrin complex was required for c-Src activation. Inhibition of c-Src had no effect on CIB1 accumulation with the integrin at the filopodia, suggesting that c-Src activity is not required for the formation of CIB1-α(IIb)-FAK complex. CONCLUSION: Our results suggest that interaction of CIB1 with α(IIb) is one of the early events occurring during outside-in signaling. Furthermore, CIB1 recruits FAK to the α(IIb)β(3) complex at the filopodia where FAK is activated, which in turn activates c-Src, resulting in propagation of outside-in signaling leading to platelet spreading. |
format | Online Article Text |
id | pubmed-5443481 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-54434812017-06-06 Binding of CIB1 to the α(IIb) tail of α(IIb)β(3) is required for FAK recruitment and activation in platelets Naik, Meghna U. Naik, Tejal U. Summer, Ross Naik, Ulhas P. PLoS One Research Article BACKGROUND: It is believed that activation of c-Src bound to the integrin β(3) subunit initiates outside-in signaling. The involvement of α(IIb) in outside-in signaling is poorly understood. OBJECTIVES: We have previously shown that CIB1 specifically interacts with the cytoplasmic domain of α(IIb) and is required for α(IIb)β(3) outside-in signaling. Here we evaluated the role of CIB1 in regulating outside-in signaling in the absence of inside-out signaling. METHODS: We used α(IIb) cytoplasmic domain peptide and CIB1-function blocking antibody to inhibit interaction of CIB1 with α(IIb) subunit as well as Cib1(-/-) platelets to evaluate the consequence of CIB1 interaction with α(IIb) on outside-in signaling. RESULTS: Fibrinogen binding to α(IIb)β(3) results in calcium-dependent interaction of CIB1 with α(IIb), which is not required for filopodia formation. Dynamic rearrangement of cytoskeleton results in CIB1-dependent recruitment of FAK to the α(IIb) complex and its activation. Disruption of the association of CIB1 and α(IIb) by incorporation of α(IIb) peptide or anti-CIB1 inhibited both FAK association and activation. Furthermore, FAK recruitment to the integrin complex was required for c-Src activation. Inhibition of c-Src had no effect on CIB1 accumulation with the integrin at the filopodia, suggesting that c-Src activity is not required for the formation of CIB1-α(IIb)-FAK complex. CONCLUSION: Our results suggest that interaction of CIB1 with α(IIb) is one of the early events occurring during outside-in signaling. Furthermore, CIB1 recruits FAK to the α(IIb)β(3) complex at the filopodia where FAK is activated, which in turn activates c-Src, resulting in propagation of outside-in signaling leading to platelet spreading. Public Library of Science 2017-05-24 /pmc/articles/PMC5443481/ /pubmed/28542214 http://dx.doi.org/10.1371/journal.pone.0176602 Text en © 2017 Naik et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
spellingShingle | Research Article Naik, Meghna U. Naik, Tejal U. Summer, Ross Naik, Ulhas P. Binding of CIB1 to the α(IIb) tail of α(IIb)β(3) is required for FAK recruitment and activation in platelets |
title | Binding of CIB1 to the α(IIb) tail of α(IIb)β(3) is required for FAK recruitment and activation in platelets |
title_full | Binding of CIB1 to the α(IIb) tail of α(IIb)β(3) is required for FAK recruitment and activation in platelets |
title_fullStr | Binding of CIB1 to the α(IIb) tail of α(IIb)β(3) is required for FAK recruitment and activation in platelets |
title_full_unstemmed | Binding of CIB1 to the α(IIb) tail of α(IIb)β(3) is required for FAK recruitment and activation in platelets |
title_short | Binding of CIB1 to the α(IIb) tail of α(IIb)β(3) is required for FAK recruitment and activation in platelets |
title_sort | binding of cib1 to the α(iib) tail of α(iib)β(3) is required for fak recruitment and activation in platelets |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5443481/ https://www.ncbi.nlm.nih.gov/pubmed/28542214 http://dx.doi.org/10.1371/journal.pone.0176602 |
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