Molecular Models of STAT5A Tetramers Complexed to DNA Predict Relative Genome-Wide Frequencies of the Spacing between the Two Dimer Binding Motifs of the Tetramer Binding Sites - Fig 5

<p>Computed scaled feasibility measures of the tetramer formation vs. CTCD using two NDDs (<b>A</b>) or at least one NDD (<b>B</b>). The red and blue points are for the ‘eclipsed’ and the ‘staggered’ tetramers, respectively, with the NDD off- and on-axis, respectively. The red and blue points were scaled so as to put them on the same scale as the experimental counts (shown in thin blue line) of tetramer binding sites in the mouse genome. For this figure, we used the DNA with 10.5 bps per helical turn. The results using the 10.0 bp DNA are given in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160339#pone.0160339.g006" target="_blank">Fig 6</a>.</p

Computed scaled feasibility measures using 10.0 bps/turn DNA.

<p>Computed scaled feasibility measures using 10.0 bps/turn DNA.</p

Computed probability sums and raw feasibility measures using 10.0 bps/turn DNA.

<p>Computed probability sums and raw feasibility measures using 10.0 bps/turn DNA.</p

A flow chart of the model building procedure.

<p>A flow chart of the model building procedure.</p

Histograms of the end-to-end distances of 13-residue peptides in protein structures in PDB, using only those peptides with the Blosum62 score greater than 8 (blue), 9 (red) or 10 (green) when compared to the linker sequence (shown in Box in Fig 1B) in STAT5A.

<p>Histograms of the end-to-end distances of 13-residue peptides in protein structures in PDB, using only those peptides with the Blosum62 score greater than 8 (blue), 9 (red) or 10 (green) when compared to the linker sequence (shown in Box in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160339#pone.0160339.g001" target="_blank">Fig 1B</a>) in STAT5A.</p

Two examples of the modeled tetramer structure.

<p>Left panels (NDD on-axis): The plan view (<b>A</b>) and elevation (<b>B</b>) of the tetramer model at the CTCD of 16; the horizontal white line is the 2-fold symmetry axis. Right panels (NDD off-axis): The plan view (<b>C</b>) and elevation (<b>D</b>) of the tetramer model at the CTCD of 21; the 2-fold axis is vertical in (C) and along the viewing direction in (D). In each panel, DNA is white; the core monomers are green (core A), blue (core D), magenta (A’), and red (D’); and NDDs are yellow. The linkers between the C-terminals of the NDD and the N-terminals of the core are indicated as dotted yellow lines.</p

The domain structure of STAT proteins.

<p><b>(A)</b> Names and positions of the six domains on the primary sequence: NTD (N-terminal domain), CCD (4-helix bundle coiled-coil domain), DBD (DNA-binding domain), LD (linker or connector domain), SH2, and TAD (transactivation domain). We treated the DBD and LD as one combined domain, as SCOP [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160339#pone.0160339.ref017" target="_blank">17</a>] does for STAT3β. There is a short flexible 13-residue linker between the NTD and CCD, which partly overlaps with the NTD. There is also a phospho-tyrosine containing segment (PTS) between the SH2 and TAD, which we combined with the TAD. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160339#sec004" target="_blank">Methods</a> for more detail. (<b>B)</b> The sequence of mouse STAT5A (NCBI Accn# CAA88419.1). The residues are highlighted according to the domains to which they belong, using the same coloring scheme used in (A). The 13-residue linker is boxed. The phospho-tyrosine residue (Y694) and the two following residues (V695 and K696) are shown in red. <b>(C)</b> STAT5A domains in the modeled structure of the STAT5A core, which includes the CCD, DBD, LD, SH2 and the residues 694–696 of the PTS. Dotted line represents the connecting residues (685–693) that were not included in the model.</p

Computed probability sums and raw feasibility measures using 10.5 bps/turn DNA.

<p>Computed probability sums and raw feasibility measures using 10.5 bps/turn DNA.</p

Image_5_Tetramerization of STAT5 regulates monocyte differentiation and the dextran sulfate sodium-induced colitis in mice.tif

In response to external stimuli during immune responses, monocytes can have multifaceted roles such as pathogen clearance and tissue repair. However, aberrant control of monocyte activation can result in chronic inflammation and subsequent tissue damage. Granulocyte-macrophage colony-stimulating factor (GM-CSF) induces monocyte differentiation into a heterogenous population of monocyte-derived dendritic cells (moDCs) and macrophages. However, the downstream molecular signals that dictate the differentiation of monocytes under pathological conditions is incompletely understood. We report here that the GM-CSF-induced STAT5 tetramerization is a critical determinate of monocyte fate and function. Monocytes require STAT5 tetramers to differentiate into moDCs. Conversely, the absence of STAT5 tetramers results in a switch to a functionally distinct monocyte-derived macrophage population. In the dextran sulfate sodium (DSS) model of colitis, STAT5 tetramer-deficient monocytes exacerbate disease severity. Mechanistically, GM-CSF signaling in STAT5 tetramer-deficient monocytes results in the overexpression of arginase I and a reduction in nitric oxide synthesis following stimulation with lipopolysaccharide. Correspondingly, the inhibition of arginase I activity and sustained supplementation of nitric oxide ameliorates the worsened colitis in STAT5 tetramer-deficient mice. This study suggests that STAT5 tetramers protect against severe intestinal inflammation through the regulation of arginine metabolism.</p

Table_4_Tetramerization of STAT5 regulates monocyte differentiation and the dextran sulfate sodium-induced colitis in mice.xls

In response to external stimuli during immune responses, monocytes can have multifaceted roles such as pathogen clearance and tissue repair. However, aberrant control of monocyte activation can result in chronic inflammation and subsequent tissue damage. Granulocyte-macrophage colony-stimulating factor (GM-CSF) induces monocyte differentiation into a heterogenous population of monocyte-derived dendritic cells (moDCs) and macrophages. However, the downstream molecular signals that dictate the differentiation of monocytes under pathological conditions is incompletely understood. We report here that the GM-CSF-induced STAT5 tetramerization is a critical determinate of monocyte fate and function. Monocytes require STAT5 tetramers to differentiate into moDCs. Conversely, the absence of STAT5 tetramers results in a switch to a functionally distinct monocyte-derived macrophage population. In the dextran sulfate sodium (DSS) model of colitis, STAT5 tetramer-deficient monocytes exacerbate disease severity. Mechanistically, GM-CSF signaling in STAT5 tetramer-deficient monocytes results in the overexpression of arginase I and a reduction in nitric oxide synthesis following stimulation with lipopolysaccharide. Correspondingly, the inhibition of arginase I activity and sustained supplementation of nitric oxide ameliorates the worsened colitis in STAT5 tetramer-deficient mice. This study suggests that STAT5 tetramers protect against severe intestinal inflammation through the regulation of arginine metabolism.</p