EF-hand protein, EfhP, specifically binds Ca 2+ and mediates Ca 2+ regulation of virulence in a human pathogen Pseudomonas aeruginosa

Calcium (Ca ) is well known as a second messenger in eukaryotes, where Ca signaling controls life-sustaining cellular processes. Although bacteria produce the components required for Ca signaling, little is known about the mechanisms of bacterial Ca signaling. Previously, we have identified a putati...

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Published in:Scientific reports 2022-05, Vol.12 (1), p.8791
Main Authors: Kayastha, Biraj B, Kubo, Aya, Burch-Konda, Jacob, Dohmen, Rosalie L, McCoy, Jacee L, Rogers, Rendi R, Mares, Sergio, Bevere, Justin, Huckaby, Annalisa, Witt, William, Peng, Shuxia, Chaudhary, Bharat, Mohanty, Smita, Barbier, Mariette, Cook, Gabriel, Deng, Junpeng, Patrauchan, Marianna A
Format: Article
Language:English
Subjects:
Calcium - metabolism
EF Hand Motifs
Humans
Pseudomonas aeruginosa - physiology
Pyocyanine - metabolism
Virulence
Virulence Factors - genetics
Virulence Factors - metabolism
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Summary:Calcium (Ca ) is well known as a second messenger in eukaryotes, where Ca signaling controls life-sustaining cellular processes. Although bacteria produce the components required for Ca signaling, little is known about the mechanisms of bacterial Ca signaling. Previously, we have identified a putative Ca -binding protein EfhP (PA4107) with two canonical EF-hand motifs and reported that EfhP mediates Ca regulation of virulence factors production and infectivity in Pseudomonas aeruginosa, a human pathogen causing life-threatening infections. Here, we show that EfhP selectively binds Ca with 13.7 µM affinity, and that mutations at the +X and -Z positions within each or both EF-hand motifs abolished Ca binding. We also show that the hydrophobicity of EfhP increased in a Ca -dependent manner, however no such response was detected in the mutated proteins.  N-NMR showed Ca -dependent chemical shifts in EfhP confirming Ca -binding triggered structural rearrangements in the protein. Deletion of efhP impaired P. aeruginosa survival in macrophages and virulence in vivo. Disabling EfhP Ca binding abolished Ca induction of pyocyanin production in vitro. These data confirm that EfhP selectively binds Ca , which triggers its structural changes required for the Ca regulation of P. aeruginosa virulence, thus establishing the role of EfhP as a Ca sensor.
ISSN:2045-2322