Two Functionally Distinct Sources of Actin Monomers Supply the Leading Edge of Lamellipodia
Lamellipodia, the sheet-like protrusions of motile cells, consist of networks of actin filaments (F-actin) regulated by the ordered assembly from and disassembly into actin monomers (G-actin). Traditionally, G-actin is thought to exist as a homogeneous pool. Here, we show that there are two function...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2015-04-01
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| Series: | Cell Reports |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2211124715003022 |
| _version_ | 1819265820316925952 |
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| author | Eric A. Vitriol Laura M. McMillen Maryna Kapustina Shawn M. Gomez Dimitrios Vavylonis James Q. Zheng |
| author_facet | Eric A. Vitriol Laura M. McMillen Maryna Kapustina Shawn M. Gomez Dimitrios Vavylonis James Q. Zheng |
| author_sort | Eric A. Vitriol |
| collection | DOAJ |
| description | Lamellipodia, the sheet-like protrusions of motile cells, consist of networks of actin filaments (F-actin) regulated by the ordered assembly from and disassembly into actin monomers (G-actin). Traditionally, G-actin is thought to exist as a homogeneous pool. Here, we show that there are two functionally and molecularly distinct sources of G-actin that supply lamellipodial actin networks. G-actin originating from the cytosolic pool requires the monomer-binding protein thymosin β4 (Tβ4) for optimal leading-edge localization, is targeted to formins, and is responsible for creating an elevated G/F-actin ratio that promotes membrane protrusion. The second source of G-actin comes from recycled lamellipodia F-actin. Recycling occurs independently of Tβ4 and appears to regulate lamellipodia homeostasis. Tβ4-bound G-actin specifically localizes to the leading edge because it does not interact with Arp2/3-mediated polymerization sites found throughout the lamellipodia. These findings demonstrate that actin networks can be constructed from multiple sources of monomers with discrete spatiotemporal functions. |
| first_indexed | 2024-12-23T20:51:27Z |
| format | Article |
| id | doaj.art-e47f3d4e156d40a9a32b645131c3248d |
| institution | Directory Open Access Journal |
| issn | 2211-1247 |
| language | English |
| last_indexed | 2024-12-23T20:51:27Z |
| publishDate | 2015-04-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Cell Reports |
| spelling | doaj.art-e47f3d4e156d40a9a32b645131c3248d2022-12-21T17:31:40ZengElsevierCell Reports2211-12472015-04-0111343344510.1016/j.celrep.2015.03.033Two Functionally Distinct Sources of Actin Monomers Supply the Leading Edge of LamellipodiaEric A. Vitriol0Laura M. McMillen1Maryna Kapustina2Shawn M. Gomez3Dimitrios Vavylonis4James Q. Zheng5Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USADepartment of Physics, Lehigh University, Bethlehem, PA 18015, USADepartment of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USADepartment of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USADepartment of Physics, Lehigh University, Bethlehem, PA 18015, USADepartment of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USALamellipodia, the sheet-like protrusions of motile cells, consist of networks of actin filaments (F-actin) regulated by the ordered assembly from and disassembly into actin monomers (G-actin). Traditionally, G-actin is thought to exist as a homogeneous pool. Here, we show that there are two functionally and molecularly distinct sources of G-actin that supply lamellipodial actin networks. G-actin originating from the cytosolic pool requires the monomer-binding protein thymosin β4 (Tβ4) for optimal leading-edge localization, is targeted to formins, and is responsible for creating an elevated G/F-actin ratio that promotes membrane protrusion. The second source of G-actin comes from recycled lamellipodia F-actin. Recycling occurs independently of Tβ4 and appears to regulate lamellipodia homeostasis. Tβ4-bound G-actin specifically localizes to the leading edge because it does not interact with Arp2/3-mediated polymerization sites found throughout the lamellipodia. These findings demonstrate that actin networks can be constructed from multiple sources of monomers with discrete spatiotemporal functions.http://www.sciencedirect.com/science/article/pii/S2211124715003022 |
| spellingShingle | Eric A. Vitriol Laura M. McMillen Maryna Kapustina Shawn M. Gomez Dimitrios Vavylonis James Q. Zheng Two Functionally Distinct Sources of Actin Monomers Supply the Leading Edge of Lamellipodia Cell Reports |
| title | Two Functionally Distinct Sources of Actin Monomers Supply the Leading Edge of Lamellipodia |
| title_full | Two Functionally Distinct Sources of Actin Monomers Supply the Leading Edge of Lamellipodia |
| title_fullStr | Two Functionally Distinct Sources of Actin Monomers Supply the Leading Edge of Lamellipodia |
| title_full_unstemmed | Two Functionally Distinct Sources of Actin Monomers Supply the Leading Edge of Lamellipodia |
| title_short | Two Functionally Distinct Sources of Actin Monomers Supply the Leading Edge of Lamellipodia |
| title_sort | two functionally distinct sources of actin monomers supply the leading edge of lamellipodia |
| url | http://www.sciencedirect.com/science/article/pii/S2211124715003022 |
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