3aa0 Citations

Two distinct mechanisms for actin capping protein regulation--steric and allosteric inhibition.

OpenAccess logo PLoS Biol 8 e1000416 (2010)
Related entries: 3aa1, 3aa6, 3aa7, 3aaa

Cited: 52 times
EuropePMC logo PMID: 20625546

Abstract

The actin capping protein (CP) tightly binds to the barbed end of actin filaments, thus playing a key role in actin-based lamellipodial dynamics. V-1 and CARMIL proteins directly bind to CP and inhibit the filament capping activity of CP. V-1 completely inhibits CP from interacting with the barbed end, whereas CARMIL proteins act on the barbed end-bound CP and facilitate its dissociation from the filament (called uncapping activity). Previous studies have revealed the striking functional differences between the two regulators. However, the molecular mechanisms describing how these proteins inhibit CP remains poorly understood. Here we present the crystal structures of CP complexed with V-1 and with peptides derived from the CP-binding motif of CARMIL proteins (CARMIL, CD2AP, and CKIP-1). V-1 directly interacts with the primary actin binding surface of CP, the C-terminal region of the alpha-subunit. Unexpectedly, the structures clearly revealed the conformational flexibility of CP, which can be attributed to a twisting movement between the two domains. CARMIL peptides in an extended conformation interact simultaneously with the two CP domains. In contrast to V-1, the peptides do not directly compete with the barbed end for the binding surface on CP. Biochemical assays revealed that the peptides suppress the interaction between CP and V-1, despite the two inhibitors not competing for the same binding site on CP. Furthermore, a computational analysis using the elastic network model indicates that the interaction of the peptides alters the intrinsic fluctuations of CP. Our results demonstrate that V-1 completely sequesters CP from the barbed end by simple steric hindrance. By contrast, CARMIL proteins allosterically inhibit CP, which appears to be a prerequisite for the uncapping activity. Our data suggest that CARMIL proteins down-regulate CP by affecting its conformational dynamics. This conceptually new mechanism of CP inhibition provides a structural basis for the regulation of the barbed end elongation in cells.

Articles - 3aa0 mentioned but not cited (3)

  1. Two distinct mechanisms for actin capping protein regulation--steric and allosteric inhibition. Takeda S, Minakata S, Koike R, Kawahata I, Narita A, Kitazawa M, Ota M, Yamakuni T, Maéda Y, Nitanai Y. PLoS Biol 8 e1000416 (2010)
  2. Mechanism for CARMIL protein inhibition of heterodimeric actin-capping protein. Kim T, Ravilious GE, Sept D, Cooper JA. J Biol Chem 287 15251-15262 (2012)
  3. Structural Investigations of N-carbamoylputrescine Amidohydrolase from Medicago truncatula: Insights into the Ultimate Step of Putrescine Biosynthesis in Plants. Sekula B, Ruszkowski M, Malinska M, Dauter Z. Front Plant Sci 7 350 (2016)


Reviews citing this publication (12)

  1. Capping protein regulators fine-tune actin assembly dynamics. Edwards M, Zwolak A, Schafer DA, Sept D, Dominguez R, Cooper JA. Nat Rev Mol Cell Biol 15 677-689 (2014)
  2. Retromer-mediated endosomal protein sorting: all WASHed up! Seaman MN, Gautreau A, Billadeau DD. Trends Cell Biol 23 522-528 (2013)
  3. Endosomal receptor trafficking: Retromer and beyond. Wang J, Fedoseienko A, Chen B, Burstein E, Jia D, Billadeau DD. Traffic 19 578-590 (2018)
  4. Control of polarized assembly of actin filaments in cell motility. Carlier MF, Pernier J, Montaville P, Shekhar S, Kühn S, Cytoskeleton Dynamics and Motility group. Cell Mol Life Sci 72 3051-3067 (2015)
  5. Regulators of actin filament barbed ends at a glance. Shekhar S, Pernier J, Carlier MF. J Cell Sci 129 1085-1091 (2016)
  6. Multiple Conformations of F-actin. Oda T, Maéda Y. Structure 18 761-767 (2010)
  7. Endosome-to-TGN Trafficking: Organelle-Vesicle and Organelle-Organelle Interactions. Tu Y, Zhao L, Billadeau DD, Jia D. Front Cell Dev Biol 8 163 (2020)
  8. Fuzziness enables context dependence of protein interactions. Miskei M, Gregus A, Sharma R, Duro N, Zsolyomi F, Fuxreiter M. FEBS Lett 591 2682-2695 (2017)
  9. Actin-Dependent Alterations of Dendritic Spine Morphology in Shankopathies. Sarowar T, Grabrucker AM. Neural Plast 2016 8051861 (2016)
  10. Structural features and interfacial properties of WH2, β-thymosin domains and other intrinsically disordered domains in the regulation of actin cytoskeleton dynamics. Renault L, Deville C, van Heijenoort C. Cytoskeleton (Hoboken) 70 686-705 (2013)
  11. Striated muscle proteins are regulated both by mechanical deformation and by chemical post-translational modification. Solís C, Russell B. Biophys Rev 13 679-695 (2021)
  12. Actin Bundles Dynamics and Architecture. Rajan S, Kudryashov DS, Reisler E. Biomolecules 13 450 (2023)

Articles citing this publication (37)