Functional Insights Into Protein Acetylation in the Hyperthermophilic Archaeon Sulfolobus islandicus*

Abstract

About 26% of the total proteins and 44% of the identified proteins were acetylated at lysine residues and the N terminus, respectively, in the hyperthermophilic archaeon Sulfolobus islandicus. A Pat homolog preferentially acetylated a group of acyl-CoA synthetases among the acetylated proteins, whereas an Ard1 homolog exhibited broad substrate specificity. A S. islandicus mutant strain lacking the Pat homolog showed no significant growth defects and that lacking the Ard1 homolog grew more slowly than the parent strain.

Post-Translational Modifications Aid Archaeal Survival

“…Recently, a proteomic analysis of a wild-type Sulfolobus islandicus strain and its mutant derivative strains lacking acetyltransferase or Nt-acetyltransferase revealed a total of 1708 Nε-acetylated lysine residues in 684 proteins (26% of the total proteins), and 158 Nt-acetylated proteins (44% of the identified proteins) have been found in S. islandicus. Additionally, consistent with the growth phenotype, the cellular levels of proteins involved in cell division and cell cycle control, DNA replication, and purine synthesis were significantly lowered in the mutant compared to the parental strain [32]. These results suggest that PTMs widely exist in thermophilic Archaea and might contribute to their adaptation to harsh living conditions.…”

The Archaeal Proteome Project advances knowledge about archaeal cell biology through comprehensive proteomics

“…With the identification of a broader range of substrates, ArcPP results suggest that Nterminal protein maturation takes place similarly for cytosolic and integral membrane proteins. Interestingly, while acetylation of uncleaved methionine was reported for H. volcanii 40 as well as the evolutionary distant S. islandicus 10 and S. solfataricus 41 , it was not detected in the closely related H. salinarum and Natronomonas pharaonis 42 . A reanalysis of Natrialba magadii proteomics data (PXD009116 43 ) revealed acetylation of uncleaved methionine as well.…”

“…Furthermore, HVO_2604 is encoded adjacent to the signal peptidase gene (sec11a, HVO_2603) and methionine aminopeptidase (HVO_2600) homologs in H. volcanii (but not in N. magadii). Alternative GNAT candidates include H. volcanii HVO_1954 and its N. magadii ortholog (Nmag_1596) as they share 3D-structural homology and conserved active site residues with the S. solfataricus SsArd1 shown to catalyze the N-acetylation of diverse protein substrates including those with methionine Ntermini 10,41,44 . We note that the deletion of SsArd1 in S. islandicus was shown to lead to growth defects 10 while alterations in N-acetylation of the 20S proteasomal alpha1 protein in H. volcanii affected growth and stress tolerance 40 , both demonstrating the importance of N-terminal acetylation.…”

“…Yet, our understanding of archaeal cell biology is lacking behind eukaryotes and bacteria. Recently, the importance of proteomics as a tool for addressing specific biological questions in archaea has become readily apparent [3][4][5][6][7][8][9][10][11][12][13] . However, such limited analyses typically leave valuable information buried in the raw data.…”

Salivary gland proteome analysis of developing adult female Haemaphysalis longicornis ticks: molecular motor and TCA cycle-related proteins play an important role throughout development

“…The GProX platform was used to cluster the salivary gland proteins with similar expression patterns in the 4 tick feeding stages [30]. The number of clusters was set to 4, and a fixed regulation threshold (upper limit of 0.58 and lower limit of − 0.58, corresponding to the original ratios of approximately 1.5 and 0.67) was used [31, 32]. The minimal membership for the plot was set as 0.5.…”