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Flexible Structure of Peptide-Bound Filamin A Mechanosensor Domain Pair 20-21.

Seppälä J, Tossavainen H, Rodic N, Permi P, Pentikäinen U, Ylänne J - PLoS ONE (2015)

Bottom Line: The atomic structures of these mechanosensor domain pairs in the resting state are known, as well as the structures of individual IgFLN21 with ligand peptides.Here, using small-angle x-ray scattering-based modelling, x-ray crystallography, and NMR, we show that the adaptor protein migfilin-derived peptide-bound structure of IgFLNa20-21 is flexible and adopts distinctive conformations depending on the presence or absence of the interacting peptide.The conformational changes reported here may be common for all peptides and may play a role in the mechanosensor function of the site.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland.

ABSTRACT
Filamins (FLNs) are large, multidomain actin cross-linking proteins with diverse functions. Besides regulating the actin cytoskeleton, they serve as important links between the extracellular matrix and the cytoskeleton by binding cell surface receptors, functioning as scaffolds for signaling proteins, and binding several other cytoskeletal proteins that regulate cell adhesion dynamics. Structurally, FLNs are formed of an amino terminal actin-binding domain followed by 24 immunoglobulin-like domains (IgFLNs). Recent studies have demonstrated that myosin-mediated contractile forces can reveal hidden protein binding sites in the domain pairs IgFLNa18-19 and 20-21, enabling FLNs to transduce mechanical signals in cells. The atomic structures of these mechanosensor domain pairs in the resting state are known, as well as the structures of individual IgFLN21 with ligand peptides. However, little experimental data is available on how interacting protein binding deforms the domain pair structures. Here, using small-angle x-ray scattering-based modelling, x-ray crystallography, and NMR, we show that the adaptor protein migfilin-derived peptide-bound structure of IgFLNa20-21 is flexible and adopts distinctive conformations depending on the presence or absence of the interacting peptide. The conformational changes reported here may be common for all peptides and may play a role in the mechanosensor function of the site.

No MeSH data available.


Related in: MedlinePlus

Migfilin peptide binding on IgFLNa∆A20–21.A Comparison of IgFLNa21-migfilin complex structure (peptide shown in orange) [18] (2W0P) with the structure reported here. Only the CD face and peptide are shown. B Electron density map (Fo–Fc) of migfilin peptide shown at σ level 2.5 calculated from the refined model without the peptide. C Same as panel B with peptide shown. D Migfilin peptide binding causes major conformational changes in IgFLNa20–21. The left panel shows the compact structure of IgFLNa20–21 from 2J3S [23]. On the right panel, the current structure and the compact structure (2J3S) are superimposed for IgFLNa21 and the compact conformation of IgFLNa20 is shown surface rendered. The two proline residues in the migfilin peptide (shown in sticks) cause a steric clash (red) for the compact orientation of IgFLNa20. The peptide sequence is given below. Density for the amino acids in the peptide written in gray was not seen.
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pone.0136969.g005: Migfilin peptide binding on IgFLNa∆A20–21.A Comparison of IgFLNa21-migfilin complex structure (peptide shown in orange) [18] (2W0P) with the structure reported here. Only the CD face and peptide are shown. B Electron density map (Fo–Fc) of migfilin peptide shown at σ level 2.5 calculated from the refined model without the peptide. C Same as panel B with peptide shown. D Migfilin peptide binding causes major conformational changes in IgFLNa20–21. The left panel shows the compact structure of IgFLNa20–21 from 2J3S [23]. On the right panel, the current structure and the compact structure (2J3S) are superimposed for IgFLNa21 and the compact conformation of IgFLNa20 is shown surface rendered. The two proline residues in the migfilin peptide (shown in sticks) cause a steric clash (red) for the compact orientation of IgFLNa20. The peptide sequence is given below. Density for the amino acids in the peptide written in gray was not seen.

Mentions: Migfilin residues 8–18 bind to the CD face of IgFLNa21 in the IgFLNaΔA20–21 construct, and prolines 19–20 bind to the top of domain 21, displacing domain 20 from the position seen in the crystal structure of FLNa19–21 [23] (Fig 5). These prolines do not form any interactions with IgFLNa21, but solely provide the necessary kink for the peptide to bind on top of the domain. Migfilin binding to the CD face is similar to that of the isolated domain 21 [18,52] (root-mean-square deviation of 0.36 Å for 89 atoms). Here we are also able to see migfilin residues 6–7, which were not seen in previous published structures [18,52]. However, these residues do not form any interactions with domain 21, although Lys7 together with Arg8 are thought to be important for the interaction with FLN [18,29].


Flexible Structure of Peptide-Bound Filamin A Mechanosensor Domain Pair 20-21.

Seppälä J, Tossavainen H, Rodic N, Permi P, Pentikäinen U, Ylänne J - PLoS ONE (2015)

Migfilin peptide binding on IgFLNa∆A20–21.A Comparison of IgFLNa21-migfilin complex structure (peptide shown in orange) [18] (2W0P) with the structure reported here. Only the CD face and peptide are shown. B Electron density map (Fo–Fc) of migfilin peptide shown at σ level 2.5 calculated from the refined model without the peptide. C Same as panel B with peptide shown. D Migfilin peptide binding causes major conformational changes in IgFLNa20–21. The left panel shows the compact structure of IgFLNa20–21 from 2J3S [23]. On the right panel, the current structure and the compact structure (2J3S) are superimposed for IgFLNa21 and the compact conformation of IgFLNa20 is shown surface rendered. The two proline residues in the migfilin peptide (shown in sticks) cause a steric clash (red) for the compact orientation of IgFLNa20. The peptide sequence is given below. Density for the amino acids in the peptide written in gray was not seen.
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Related In: Results  -  Collection

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pone.0136969.g005: Migfilin peptide binding on IgFLNa∆A20–21.A Comparison of IgFLNa21-migfilin complex structure (peptide shown in orange) [18] (2W0P) with the structure reported here. Only the CD face and peptide are shown. B Electron density map (Fo–Fc) of migfilin peptide shown at σ level 2.5 calculated from the refined model without the peptide. C Same as panel B with peptide shown. D Migfilin peptide binding causes major conformational changes in IgFLNa20–21. The left panel shows the compact structure of IgFLNa20–21 from 2J3S [23]. On the right panel, the current structure and the compact structure (2J3S) are superimposed for IgFLNa21 and the compact conformation of IgFLNa20 is shown surface rendered. The two proline residues in the migfilin peptide (shown in sticks) cause a steric clash (red) for the compact orientation of IgFLNa20. The peptide sequence is given below. Density for the amino acids in the peptide written in gray was not seen.
Mentions: Migfilin residues 8–18 bind to the CD face of IgFLNa21 in the IgFLNaΔA20–21 construct, and prolines 19–20 bind to the top of domain 21, displacing domain 20 from the position seen in the crystal structure of FLNa19–21 [23] (Fig 5). These prolines do not form any interactions with IgFLNa21, but solely provide the necessary kink for the peptide to bind on top of the domain. Migfilin binding to the CD face is similar to that of the isolated domain 21 [18,52] (root-mean-square deviation of 0.36 Å for 89 atoms). Here we are also able to see migfilin residues 6–7, which were not seen in previous published structures [18,52]. However, these residues do not form any interactions with domain 21, although Lys7 together with Arg8 are thought to be important for the interaction with FLN [18,29].

Bottom Line: The atomic structures of these mechanosensor domain pairs in the resting state are known, as well as the structures of individual IgFLN21 with ligand peptides.Here, using small-angle x-ray scattering-based modelling, x-ray crystallography, and NMR, we show that the adaptor protein migfilin-derived peptide-bound structure of IgFLNa20-21 is flexible and adopts distinctive conformations depending on the presence or absence of the interacting peptide.The conformational changes reported here may be common for all peptides and may play a role in the mechanosensor function of the site.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland.

ABSTRACT
Filamins (FLNs) are large, multidomain actin cross-linking proteins with diverse functions. Besides regulating the actin cytoskeleton, they serve as important links between the extracellular matrix and the cytoskeleton by binding cell surface receptors, functioning as scaffolds for signaling proteins, and binding several other cytoskeletal proteins that regulate cell adhesion dynamics. Structurally, FLNs are formed of an amino terminal actin-binding domain followed by 24 immunoglobulin-like domains (IgFLNs). Recent studies have demonstrated that myosin-mediated contractile forces can reveal hidden protein binding sites in the domain pairs IgFLNa18-19 and 20-21, enabling FLNs to transduce mechanical signals in cells. The atomic structures of these mechanosensor domain pairs in the resting state are known, as well as the structures of individual IgFLN21 with ligand peptides. However, little experimental data is available on how interacting protein binding deforms the domain pair structures. Here, using small-angle x-ray scattering-based modelling, x-ray crystallography, and NMR, we show that the adaptor protein migfilin-derived peptide-bound structure of IgFLNa20-21 is flexible and adopts distinctive conformations depending on the presence or absence of the interacting peptide. The conformational changes reported here may be common for all peptides and may play a role in the mechanosensor function of the site.

No MeSH data available.


Related in: MedlinePlus