Change of Carbon Source Causes Dramatic Effects in the Phospho-Proteome of the Archaeon Sulfolobus solfataricus

Abstract

Protein phosphorylation is known to occur in Archaea. However, knowledge of phosphorylation in the third domain of life is rather scarce. Homology-based searches of archaeal genome sequences reveals the absence of two-component systems in crenarchaeal genomes but the presence of eukaryotic-like protein kinases and protein phosphatases. Here, the influence of the offered carbon source (glucose versus tryptone) on the phospho-proteome of Sulfolobus solfataricus P2 was studied by precursor acquisition independent from ion count (PAcIFIC). In comparison to previous phospho-proteome studies, a high number of phosphorylation sites (1318) located on 690 phospho-peptides from 540 unique phospho-proteins were detected, thus increasing the number of currently known archaeal phospho-proteins from 80 to 621. Furthermore, a 25.8/20.6/53.6 Ser/Thr/Tyr percentage ratio with an unexpectedly high predominance of tyrosine phosphorylation was detected. Phospho-proteins in most functional classes (21 out of 26 arCOGs) were identified, suggesting an important regulatory role in S. solfataricus. Focusing on the central carbohydrate metabolism in response to the offered carbon source, significant changes were observed. The observed complex phosphorylation pattern hints at an important physiological function of protein phosphorylation in control of the central carbohydrate metabolism, which might particularly operate in channeling carbon flux into the respective metabolic pathways.

Carbohydrate Metabolism in Archaea: Current Insights into Unusual Enzymes and Pathways and Their Regulation

“…For Sul. solfataricus, a complex phosphorylation pattern of CCM enzymes with significant changes in response to the offered carbon source was observed (439).…”

“…solfataricus P2 in response to different carbon sources (glucose versus tryptone) was investigated. The applied gel-and enrichment-free PAcIFIC (precursor acquisition independent from ion count) approach (438) revealed an unexpectedly large number of phosphoproteins (540 phosphoproteins) as well as a large amount of p-Tyr (54%) (439). The identified phosphoproteins are located in 21 out of 26 arCOG categories (440), indicating that most of the cellular processes are targeted by protein phosphorylation.…”

“…Effectors are given in green and red boxes for activators and inhibitors, respectively. Enzymes identified as phosphoproteins under glycolytic (glucose) or gluconeogenic (tryptone) growth conditions are marked by black dots, with T for tryptone and G for glucose (439). Enzymes that were upregulated (Ͼ1.5-fold) at the protein level in response to glucose or complex medium (tryptone and yeast extract) are marked with red and blue open arrows, respectively (505).…”

Archaeal Aldehyde Dehydrogenase ST0064 fromSulfolobus tokodaii, a Paralog of Non-Phosphorylating Glyceraldehyde-3-phosphate Dehydrogenase, Is a Succinate Semialdehyde Dehydrogenase

“…The solid triangle indicates the catalytic base of CoAindependent aldehyde dehydrogenase, and the hollow triangle indicates the phosphorylated Ser in Sso1842. 19) 100%, 99-80%, and 79-60% conserved similar residues among all sequences are shown against black, dark gray, and light gray backgrounds respectively. identified in Ttx-GAPN, but it was not conserved in the ST0064 orthologs.…”

“…A recent proteomic study of S. solfataricus, found that Ser436 of Sso1842, an ST0064 ortholog, is phosphorylated in glucose-grown cells. 19) Ser at this position is moderately conserved among ST0064 orthologs (Fig. 1, hollow triangle), and there is a possibility that phosphorylation of this Ser was involved in the regulation of SSADH.…”