Legionella pneumophila Requires Polyamines for Optimal Intracellular Growth

Abstract

Volume 193, no. 17, pages 4346 -4360, 2011. Page 4355: We erroneously stated, "The only genes encoding polyamine biosynthetic enzymes in L. pneumophila were metK (methionine adenosyltransferase) and speA (arginine decarboxylase). 1-14, 1998). The other two enzymes encoded in the arginine decarboxylase (speA) locus in L. pneumophila genomes are agmatine deiminase and N-carbamoyl putrescine amidohydrolase. We did not account for these three enzymes, mainly because in our bioinformatics analysis we looked only for the conventional polyamine biosynthetic enzymes present in Escherichia coli and Vibrio cholerae. We thus acknowledge here the presence of a complete putrescine-homospermidine alternative biosynthetic pathway in Legionella. Our suggestion that "L. pneumophila cannot synthesize all polyamines" (end of p. 4355) still stands, and our finding that L. pneumophila grows better in the presence of putrescine, spermidine, and/or spermine is not affected by this correction.

A yeast two-hybrid screen reveals a strong interaction between the Legionella chaperonin Hsp60 and the host cell small heat shock protein Hsp10

“…In addition to the aforementioned fi ndings, we have recently found other evidence that clearly demonstrate that HtpB plays multifunctional role L. pneumphila life cycle [7]. For instance, we showed that a small portion of the accumulated HtpB in L. pneumophila LCV was released in the cytoplasm of the infected cells, as judged by the CyaA reporter assay [7].…”

“…For example, Group I chaperonins are proteins found in bacteria (known as Cpn60, GroEL, Hsp60, or HtpB), and in eukaryotic organelles such as chloroplasts and mitochondria (known as CCT, TRiC or c-cpn) [4]. A comparison of the aligned amino acid sequences of the eukaryotic chaperonins and bacterial chaperonins (including HtpB) revealed that these proteins have high degrees of amino acid homology that sometimes exceed 70% [4][5][6][7][8]. To function properly in protein folding, bacterial or eukaryotic chaperonins must work in conjunction with a small heat shock protein (~10 kDa) known as Hsp10 or Cpn10 (also known as GroES in bacteria and HtpA in L. pneumophila) [4,9,10].…”

“…For instance, we showed that a small portion of the accumulated HtpB in L. pneumophila LCV was released in the cytoplasm of the infected cells, as judged by the CyaA reporter assay [7]. To identify potential functions of the HtpB present in the eukaryotic cytoplasm, htpB was ectopically expressed in Saccharomyces cerevisiae.…”

“…To identify potential functions of the HtpB present in the eukaryotic cytoplasm, htpB was ectopically expressed in Saccharomyces cerevisiae. HtpB expression induced pseudohyphal growth (PHG) in yeast, suggesting it interacts with eukaryotic targets [7]. Using a yeast two-hybrid screen (Y2H), we showed that HtpB interacted with S-adenosyl methionine decarboxylase (SAMDC), an essential conserved enzyme required for synthesis of polyamines [7].…”

Putrescine Importer PlaP Contributes to Swarming Motility and Urothelial Cell Invasion in Proteus mirabilis

“…For example, in Salmonella enterica sv. typhimurium, polyamines are required for virulence (13); in Legionella pneumophila, intracellular growth is enhanced by polyamines derived from host cells (14), and in Streptococcus pneumoniae, polyamine biosynthetic pathways and the spermidine transporter PotABCD are important for infection (15,16).…”