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Proteome-wide lysine acetylation in cortical astrocytes and alterations that occur during infection with brain parasite Toxoplasma gondii.

Bouchut A, Chawla AR, Jeffers V, Hudmon A, Sullivan WJ - PLoS ONE (2015)

Bottom Line: We identified 529 lysine acetylation sites across 304 proteins found in multiple cellular compartments that largely function in RNA processing/transcription, metabolism, chromatin biology, and translation.We also mapped an acetylome of astrocytes infected with the brain parasite, Toxoplasma gondii.In the T. gondii-infected astrocytes, we identified 34 proteins exhibiting a level of acetylation >2-fold and 24 with a level of acetylation <2-fold relative to uninfected astrocytes.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, IN, 46202, United States of America.

ABSTRACT
Lysine acetylation is a reversible post-translational modification (PTM) that has been detected on thousands of proteins in nearly all cellular compartments. The role of this widespread PTM has yet to be fully elucidated, but can impact protein localization, interactions, activity, and stability. Here we present the first proteome-wide survey of lysine acetylation in cortical astrocytes, a subtype of glia that is a component of the blood-brain barrier and a key regulator of neuronal function and plasticity. We identified 529 lysine acetylation sites across 304 proteins found in multiple cellular compartments that largely function in RNA processing/transcription, metabolism, chromatin biology, and translation. Two hundred and seventy-seven of the acetylated lysines we identified on 186 proteins have not been reported previously in any other cell type. We also mapped an acetylome of astrocytes infected with the brain parasite, Toxoplasma gondii. It has been shown that infection with T. gondii modulates host cell gene expression, including several lysine acetyltransferase (KAT) and deacetylase (KDAC) genes, suggesting that the host acetylome may also be altered during infection. In the T. gondii-infected astrocytes, we identified 34 proteins exhibiting a level of acetylation >2-fold and 24 with a level of acetylation <2-fold relative to uninfected astrocytes. Our study documents the first acetylome map for cortical astrocytes, uncovers novel lysine acetylation sites, and demonstrates that T. gondii infection produces an altered acetylome.

No MeSH data available.


Related in: MedlinePlus

Analysis of acetylated lysine sites.A. Heat map of amino acid composition of acetylation sites in Rattus norvegicus astrocytes, displaying amino acids that are significantly enriched (green) or absent (red) relative to the general amino acid composition of the Rattus norvegicus proteome. B. Sequence motifs of astrocyte acetylation sites +/-7 amino acids from the targeted lysine residue. Motifs were compiled using all acetylated peptides or only those found in histones, non-histone proteins, or mitochondrial proteins.
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pone.0117966.g004: Analysis of acetylated lysine sites.A. Heat map of amino acid composition of acetylation sites in Rattus norvegicus astrocytes, displaying amino acids that are significantly enriched (green) or absent (red) relative to the general amino acid composition of the Rattus norvegicus proteome. B. Sequence motifs of astrocyte acetylation sites +/-7 amino acids from the targeted lysine residue. Motifs were compiled using all acetylated peptides or only those found in histones, non-histone proteins, or mitochondrial proteins.

Mentions: We also assessed if the amino acids flanking the targeted acetyl-lysine exhibits bias towards a certain motif and if there is significant enrichment or absence of specific amino acids with respect to the general amino acid composition of the entire Rattus norvegicus proteome. For these analyses, we generated WebLogo sequence motifs [40] and IceLogo heat maps [69]. As previously reported for multiple cell types, we found that lysine acetylation of astrocyte proteins also generally occurs in lysine-rich regions, with a significant enrichment for glycine and alanine at positions-1, -2, and-3 and positions +1, +2, and +5 for alanine only, as shown in Fig. 4A [27,28]. The heat map also shows an absence of serine, proline, and histidine at position +1, and a general lack of leucine in the vicinity of the acetylation site. However, the preponderance of histone proteins in acetylome datasets likely biases the global motif analysis; searching for only the acetylated proteins in mitochondria reveals a striking deviance from other acetylation sites (Fig. 4B). In the acetylated proteins in astrocyte mitochondria, there is a modest enrichment for glutamate (E) at the-1 position, which has been observed before in multiple studies [70]. Analysis of the histone proteins alone revealed a high conservation of the GK motif, with additional lysines at the + and—4 positions, consistent with acetylated histones in other species and cell types [28,58]. Our data lends support to the idea that different motifs are targeted by distinct KATs residing in that particular cellular compartment [70].


Proteome-wide lysine acetylation in cortical astrocytes and alterations that occur during infection with brain parasite Toxoplasma gondii.

Bouchut A, Chawla AR, Jeffers V, Hudmon A, Sullivan WJ - PLoS ONE (2015)

Analysis of acetylated lysine sites.A. Heat map of amino acid composition of acetylation sites in Rattus norvegicus astrocytes, displaying amino acids that are significantly enriched (green) or absent (red) relative to the general amino acid composition of the Rattus norvegicus proteome. B. Sequence motifs of astrocyte acetylation sites +/-7 amino acids from the targeted lysine residue. Motifs were compiled using all acetylated peptides or only those found in histones, non-histone proteins, or mitochondrial proteins.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4364782&req=5

pone.0117966.g004: Analysis of acetylated lysine sites.A. Heat map of amino acid composition of acetylation sites in Rattus norvegicus astrocytes, displaying amino acids that are significantly enriched (green) or absent (red) relative to the general amino acid composition of the Rattus norvegicus proteome. B. Sequence motifs of astrocyte acetylation sites +/-7 amino acids from the targeted lysine residue. Motifs were compiled using all acetylated peptides or only those found in histones, non-histone proteins, or mitochondrial proteins.
Mentions: We also assessed if the amino acids flanking the targeted acetyl-lysine exhibits bias towards a certain motif and if there is significant enrichment or absence of specific amino acids with respect to the general amino acid composition of the entire Rattus norvegicus proteome. For these analyses, we generated WebLogo sequence motifs [40] and IceLogo heat maps [69]. As previously reported for multiple cell types, we found that lysine acetylation of astrocyte proteins also generally occurs in lysine-rich regions, with a significant enrichment for glycine and alanine at positions-1, -2, and-3 and positions +1, +2, and +5 for alanine only, as shown in Fig. 4A [27,28]. The heat map also shows an absence of serine, proline, and histidine at position +1, and a general lack of leucine in the vicinity of the acetylation site. However, the preponderance of histone proteins in acetylome datasets likely biases the global motif analysis; searching for only the acetylated proteins in mitochondria reveals a striking deviance from other acetylation sites (Fig. 4B). In the acetylated proteins in astrocyte mitochondria, there is a modest enrichment for glutamate (E) at the-1 position, which has been observed before in multiple studies [70]. Analysis of the histone proteins alone revealed a high conservation of the GK motif, with additional lysines at the + and—4 positions, consistent with acetylated histones in other species and cell types [28,58]. Our data lends support to the idea that different motifs are targeted by distinct KATs residing in that particular cellular compartment [70].

Bottom Line: We identified 529 lysine acetylation sites across 304 proteins found in multiple cellular compartments that largely function in RNA processing/transcription, metabolism, chromatin biology, and translation.We also mapped an acetylome of astrocytes infected with the brain parasite, Toxoplasma gondii.In the T. gondii-infected astrocytes, we identified 34 proteins exhibiting a level of acetylation >2-fold and 24 with a level of acetylation <2-fold relative to uninfected astrocytes.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, IN, 46202, United States of America.

ABSTRACT
Lysine acetylation is a reversible post-translational modification (PTM) that has been detected on thousands of proteins in nearly all cellular compartments. The role of this widespread PTM has yet to be fully elucidated, but can impact protein localization, interactions, activity, and stability. Here we present the first proteome-wide survey of lysine acetylation in cortical astrocytes, a subtype of glia that is a component of the blood-brain barrier and a key regulator of neuronal function and plasticity. We identified 529 lysine acetylation sites across 304 proteins found in multiple cellular compartments that largely function in RNA processing/transcription, metabolism, chromatin biology, and translation. Two hundred and seventy-seven of the acetylated lysines we identified on 186 proteins have not been reported previously in any other cell type. We also mapped an acetylome of astrocytes infected with the brain parasite, Toxoplasma gondii. It has been shown that infection with T. gondii modulates host cell gene expression, including several lysine acetyltransferase (KAT) and deacetylase (KDAC) genes, suggesting that the host acetylome may also be altered during infection. In the T. gondii-infected astrocytes, we identified 34 proteins exhibiting a level of acetylation >2-fold and 24 with a level of acetylation <2-fold relative to uninfected astrocytes. Our study documents the first acetylome map for cortical astrocytes, uncovers novel lysine acetylation sites, and demonstrates that T. gondii infection produces an altered acetylome.

No MeSH data available.


Related in: MedlinePlus