Actin Binding Domains Direct Actin-Binding Proteins to Different Cytoskeletal Locations

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Actin Binding Domains Direct Actin-Binding Proteins to Different Cytoskeletal Locations

Show simple item record Knecht, David A Washington, Raymond William 2011-04-11T14:37:17Z 2008
dc.identifier.citation Washington, Raymond W., and David A. Knecht. 2008. Actin binding domains direct actin-binding proteins to different cytoskeletal locations. BMC Cell Biology 9: 10. en_US
dc.identifier.issn 1471-2121 en_US
dc.description.abstract Background: Filamin (FLN) and non-muscle α-actinin are members of a family of F-actin cross-linking proteins that utilize Calponin Homology domains (CH-domain) for actin binding. Although these two proteins have been extensively characterized, little is known about what regulates their binding to F-actin filaments in the cell. Results: We have constructed fusion proteins consisting of green fluorescent protein (GFP) with either the entire cross-linking protein or its actin-binding domain (ABD) and examined the localization of these fluorescent proteins in living cells under a variety of conditions. The full-length fusion proteins, but not the ABD's complemented the defects of cells lacking both endogenous proteins indicating that they are functional. The localization patterns of filamin (GFP-FLN) and α-actinin (GFP-αA) were overlapping but distinct. GFP-FLN localized to the peripheral cell cortex as well as to new pseudopods of unpolarized cells, but was observed to localize to the rear of polarized cells during cAMP and folate chemotaxis. GFP-αA was enriched in new pseudopods and at the front of polarized cells, but in all cases was absent from the peripheral cortex. Although both proteins appear to be involved in macropinocytosis, the association time of the GFP-probes with the internalized macropinosome differed. Surprisingly, the localization of the GFP-actin-binding domain fusion proteins precisely reflected that of their respective full length constructs, indicating that the localization of the protein was determined by the actin-binding domain alone. When expressed in a cell line lacking both filamin and α-actinin, the probes maintain their distinct localization patterns suggesting that they are not functionally redundant. Conclusion: These observations strongly suggest that the regulation of the binding of these proteins to actin filaments is built into the actin-binding domains. We suggest that different actin binding domains have different affinities for F-actin filaments in functionally distinct regions of the cytoskeleton. en_US
dc.language.iso en_US en_US
dc.publisher BioMed Central en_US
dc.relation.isversionof doi:10.1186/1471-2121-9-10 en_US
dc.relation.hasversion en_US
dash.license LAA
dc.title Actin Binding Domains Direct Actin-Binding Proteins to Different Cytoskeletal Locations en_US
dc.type Journal Article en_US
dc.description.version Version of Record en_US
dc.relation.journal BMC Cell Biology en_US Washington, Raymond William 2011-04-11T14:37:17Z
dash.affiliation.other HMS^Pathology en_US

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