Structural Study of the WH2 Family and Filamin: Implications for Actin Cytoskeleton Regulation
Cellular processes like motility, chemotaxis, phagocytosis and morphogenesis are dependent on the dynamic regulation of the actin cytoskeleton. This cytoskeleton system is tightly controlled by a number of diverse actin-binding proteins (ABPs) by various mechanisms described as nucleation, polymeriz...
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2006
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ndltd-UPSALLA1-oai-DiVA.org-uu-71882013-01-08T13:04:22ZStructural Study of the WH2 Family and Filamin: Implications for Actin Cytoskeleton RegulationengAguda, Adeleke H.Uppsala universitet, Institutionen för medicinsk biokemi och mikrobiologiUppsala : Acta Universitatis Upsaliensis2006BiochemistryActinThymosinCiboulotN-WASPFilaminCalponin homology domainWH2Protein CrystallographyBiokemiCellular processes like motility, chemotaxis, phagocytosis and morphogenesis are dependent on the dynamic regulation of the actin cytoskeleton. This cytoskeleton system is tightly controlled by a number of diverse actin-binding proteins (ABPs) by various mechanisms described as nucleation, polymerization, capping, severing, depolymerization and sequestration. The ABPs are grouped based on sequence identity as in the Wiskott-Aldrich Syndrome protein homology domain 2 (WH2), and the calponin homology domain (CH) containing proteins. In this work, we elucidate the crystal structures of hybrids of gelsolin domain 1 with thymosin β4, ciboulot domain 2, and the second WH2 domain of N-WASP each bound to actin. We show that the single WH2 motif containing protein thymosin β4 in part sequesters actin by binding its pointed end via a C-terminal helix. This interaction prevents the addition of bound actin protomers to the barbed end of the filament. We propose that sequence variations in some WH2 motifs conferred F-actin binding ability to multiple repeat-containing proteins. These F-actin binding domains interact with the barbed end of a filament and the adjacent WH2 motifs are then freed to add their bound actin to the growing filament end. We demonstrate the binding of ciboulot domains 2 and 3 to both G- and F-actin and that full length ciboulot is capable of binding two actin monomers simultaneously. We have also cloned, expressed, purified and crystallized rod domains 14-16 from the actin crosslinking protein a-filamin. Preliminary X-ray crystallography data gives us hope that we shall be able to solve the structure of this triple domain repeat. Doctoral thesis, comprehensive summaryinfo:eu-repo/semantics/doctoralThesistexthttp://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7188urn:isbn:91-554-6679-6Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, 1651-6206 ; 182application/pdfinfo:eu-repo/semantics/openAccess |
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English |
format |
Doctoral Thesis |
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Biochemistry Actin Thymosin Ciboulot N-WASP Filamin Calponin homology domain WH2 Protein Crystallography Biokemi |
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Biochemistry Actin Thymosin Ciboulot N-WASP Filamin Calponin homology domain WH2 Protein Crystallography Biokemi Aguda, Adeleke H. Structural Study of the WH2 Family and Filamin: Implications for Actin Cytoskeleton Regulation |
description |
Cellular processes like motility, chemotaxis, phagocytosis and morphogenesis are dependent on the dynamic regulation of the actin cytoskeleton. This cytoskeleton system is tightly controlled by a number of diverse actin-binding proteins (ABPs) by various mechanisms described as nucleation, polymerization, capping, severing, depolymerization and sequestration. The ABPs are grouped based on sequence identity as in the Wiskott-Aldrich Syndrome protein homology domain 2 (WH2), and the calponin homology domain (CH) containing proteins. In this work, we elucidate the crystal structures of hybrids of gelsolin domain 1 with thymosin β4, ciboulot domain 2, and the second WH2 domain of N-WASP each bound to actin. We show that the single WH2 motif containing protein thymosin β4 in part sequesters actin by binding its pointed end via a C-terminal helix. This interaction prevents the addition of bound actin protomers to the barbed end of the filament. We propose that sequence variations in some WH2 motifs conferred F-actin binding ability to multiple repeat-containing proteins. These F-actin binding domains interact with the barbed end of a filament and the adjacent WH2 motifs are then freed to add their bound actin to the growing filament end. We demonstrate the binding of ciboulot domains 2 and 3 to both G- and F-actin and that full length ciboulot is capable of binding two actin monomers simultaneously. We have also cloned, expressed, purified and crystallized rod domains 14-16 from the actin crosslinking protein a-filamin. Preliminary X-ray crystallography data gives us hope that we shall be able to solve the structure of this triple domain repeat. |
author |
Aguda, Adeleke H. |
author_facet |
Aguda, Adeleke H. |
author_sort |
Aguda, Adeleke H. |
title |
Structural Study of the WH2 Family and Filamin: Implications for Actin Cytoskeleton Regulation |
title_short |
Structural Study of the WH2 Family and Filamin: Implications for Actin Cytoskeleton Regulation |
title_full |
Structural Study of the WH2 Family and Filamin: Implications for Actin Cytoskeleton Regulation |
title_fullStr |
Structural Study of the WH2 Family and Filamin: Implications for Actin Cytoskeleton Regulation |
title_full_unstemmed |
Structural Study of the WH2 Family and Filamin: Implications for Actin Cytoskeleton Regulation |
title_sort |
structural study of the wh2 family and filamin: implications for actin cytoskeleton regulation |
publisher |
Uppsala universitet, Institutionen för medicinsk biokemi och mikrobiologi |
publishDate |
2006 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7188 http://nbn-resolving.de/urn:isbn:91-554-6679-6 |
work_keys_str_mv |
AT agudaadelekeh structuralstudyofthewh2familyandfilaminimplicationsforactincytoskeletonregulation |
_version_ |
1716508151210049536 |