Ena/VASP processive elongation is modulated by avidity on actin filaments bundled by the filopodia cross-linker fascin. 2019

Alyssa J Harker, and Harshwardhan H Katkar, and Tamara C Bidone, and Fikret Aydin, and Gregory A Voth, and Derek A Applewhite, and David R Kovar
Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637.

Ena/VASP tetramers are processive actin elongation factors that localize to diverse F-actin networks composed of filaments bundled by different cross-linking proteins, such as filopodia (fascin), lamellipodia (fimbrin), and stress fibers (α-actinin). Previously, we found that Ena takes approximately threefold longer processive runs on trailing barbed ends of fascin-bundled F-actin. Here, we used single-molecule TIRFM (total internal reflection fluorescence microscopy) and developed a kinetic model to further dissect Ena/VASP's processive mechanism on bundled filaments. We discovered that Ena's enhanced processivity on trailing barbed ends is specific to fascin bundles, with no enhancement on fimbrin or α-actinin bundles. Notably, Ena/VASP's processive run length increases with the number of both fascin-bundled filaments and Ena "arms," revealing avidity facilitates enhanced processivity. Consistently, Ena tetramers form more filopodia than mutant dimer and trimers in Drosophila culture cells. Moreover, enhanced processivity on trailing barbed ends of fascin-bundled filaments is an evolutionarily conserved property of Ena/VASP homologues, including human VASP and Caenorhabditis elegans UNC-34. These results demonstrate that Ena tetramers are tailored for enhanced processivity on fascin bundles and that avidity of multiple arms associating with multiple filaments is critical for this process. Furthermore, we discovered a novel regulatory process whereby bundle size and bundling protein specificity control activities of a processive assembly factor.

UI MeSH Term Description Entries
D007700 Kinetics The rate dynamics in chemical or physical systems.
D008840 Microfilament Proteins Monomeric subunits of primarily globular ACTIN and found in the cytoplasmic matrix of almost all cells. They are often associated with microtubules and may play a role in cytoskeletal function and/or mediate movement of the cell or the organelles within the cell. Actin Binding Protein,Actin-Binding Protein,Actin-Binding Proteins,Microfilament Protein,Actin Binding Proteins,Binding Protein, Actin,Protein, Actin Binding,Protein, Actin-Binding,Protein, Microfilament,Proteins, Actin-Binding,Proteins, Microfilament
D008841 Actin Cytoskeleton Fibers composed of MICROFILAMENT PROTEINS, which are predominately ACTIN. They are the smallest of the cytoskeletal filaments. Actin Filaments,Microfilaments,Actin Microfilaments,Actin Cytoskeletons,Actin Filament,Actin Microfilament,Cytoskeleton, Actin,Cytoskeletons, Actin,Filament, Actin,Filaments, Actin,Microfilament,Microfilament, Actin,Microfilaments, Actin
D008856 Microscopy, Fluorescence Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye. Fluorescence Microscopy,Immunofluorescence Microscopy,Microscopy, Immunofluorescence,Fluorescence Microscopies,Immunofluorescence Microscopies,Microscopies, Fluorescence,Microscopies, Immunofluorescence
D010441 Peptide Chain Elongation, Translational A process of GENETIC TRANSLATION, when an amino acid is transferred from its cognate TRANSFER RNA to the lengthening chain of PEPTIDES. Chain Elongation, Peptide, Translational,Protein Biosynthesis Elongation,Protein Chain Elongation, Translational,Protein Translation Elongation,Translation Elongation, Genetic,Translation Elongation, Protein,Translational Elongation, Protein,Translational Peptide Chain Elongation,Biosynthesis Elongation, Protein,Elongation, Genetic Translation,Elongation, Protein Biosynthesis,Elongation, Protein Translation,Elongation, Protein Translational,Genetic Translation Elongation,Protein Translational Elongation
D011485 Protein Binding The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments. Plasma Protein Binding Capacity,Binding, Protein
D011554 Pseudopodia A dynamic actin-rich extension of the surface of an animal cell used for locomotion or prehension of food. Axopodia,Filopodia,Lamellipodia,Lobopodia,Microspikes, Cell Surface,Reticulopodia,Pseudopodium,Cell Surface Microspike,Cell Surface Microspikes,Lamellipodias,Microspike, Cell Surface,Surface Microspike, Cell,Surface Microspikes, Cell
D002352 Carrier Proteins Proteins that bind or transport specific substances in the blood, within the cell, or across cell membranes. Binding Proteins,Carrier Protein,Transport Protein,Transport Proteins,Binding Protein,Protein, Carrier,Proteins, Carrier
D002460 Cell Line Established cell cultures that have the potential to propagate indefinitely. Cell Lines,Line, Cell,Lines, Cell
D003598 Cytoskeletal Proteins Major constituent of the cytoskeleton found in the cytoplasm of eukaryotic cells. They form a flexible framework for the cell, provide attachment points for organelles and formed bodies, and make communication between parts of the cell possible. Proteins, Cytoskeletal

Related Publications

Alyssa J Harker, and Harshwardhan H Katkar, and Tamara C Bidone, and Fikret Aydin, and Gregory A Voth, and Derek A Applewhite, and David R Kovar
March 2014, Proceedings of the National Academy of Sciences of the United States of America,
Alyssa J Harker, and Harshwardhan H Katkar, and Tamara C Bidone, and Fikret Aydin, and Gregory A Voth, and Derek A Applewhite, and David R Kovar
April 1980, Experimental cell research,
Alyssa J Harker, and Harshwardhan H Katkar, and Tamara C Bidone, and Fikret Aydin, and Gregory A Voth, and Derek A Applewhite, and David R Kovar
July 2017, Proceedings of the National Academy of Sciences of the United States of America,
Alyssa J Harker, and Harshwardhan H Katkar, and Tamara C Bidone, and Fikret Aydin, and Gregory A Voth, and Derek A Applewhite, and David R Kovar
February 2011, The EMBO journal,
Alyssa J Harker, and Harshwardhan H Katkar, and Tamara C Bidone, and Fikret Aydin, and Gregory A Voth, and Derek A Applewhite, and David R Kovar
August 2015, eLife,
Alyssa J Harker, and Harshwardhan H Katkar, and Tamara C Bidone, and Fikret Aydin, and Gregory A Voth, and Derek A Applewhite, and David R Kovar
May 2009, The Journal of biological chemistry,
Alyssa J Harker, and Harshwardhan H Katkar, and Tamara C Bidone, and Fikret Aydin, and Gregory A Voth, and Derek A Applewhite, and David R Kovar
October 2007, The EMBO journal,
Alyssa J Harker, and Harshwardhan H Katkar, and Tamara C Bidone, and Fikret Aydin, and Gregory A Voth, and Derek A Applewhite, and David R Kovar
November 2008, The EMBO journal,
Alyssa J Harker, and Harshwardhan H Katkar, and Tamara C Bidone, and Fikret Aydin, and Gregory A Voth, and Derek A Applewhite, and David R Kovar
November 2022, Science advances,
Alyssa J Harker, and Harshwardhan H Katkar, and Tamara C Bidone, and Fikret Aydin, and Gregory A Voth, and Derek A Applewhite, and David R Kovar
January 2011, Cell adhesion & migration,
Copied contents to your clipboard!