Calmodulin-like protein from M. tuberculosis H37Rv is required during infection

Advani, Meeta J.; Rajagopalan, Malini; Reddy, P. Madhusudhana

doi:10.1038/srep06861

Cited by 7 publications

(2 citation statements)

References 33 publications

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“…M. smegmatis has a calmodulin-like protein (CAMLP) with functional similarity to eukaryotic calmodulin ( 28 ). This protein was implicated to have a role in phospholipid metabolism ( 29 ), and CAMLP from Mycobacterium tuberculosis has recently been shown to be important during infection ( 30 ). A. Ca 2+ /calmodulin-dependent protein kinase (Cam-kinase) was also purified and characterized from M. smegmatis ( 31 ), but direct roles of these proteins in gene regulation in M. smegmatis remain unexplored.…”

Section: Discussionmentioning

confidence: 99%

A Novel Calcium Uptake Transporter of Uncharacterized P-Type ATPase Family Supplies Calcium for Cell Surface Integrity in Mycobacterium smegmatis

Gupta

Shrivastava

Sharma

2017

mBio

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Ca2+ plays an important role in the physiology of bacteria. Intracellular Ca2+ concentrations are tightly maintained in the nanomolar range. Molecular mechanisms of Ca2+ uptake in bacteria remain elusive. Here we show that CtpE is responsible for Ca2+ uptake in Mycobacterium smegmatis. It represents a previously uncharacterized P-type ATPase family in bacteria. Disruption of ctpE in M. smegmatis resulted in a mutant with impaired growth under Ca2+-deficient conditions. The growth defect of the mutant could be rescued by Ca2+ or by ectopic expression of ctpE from M. smegmatis or the orthologous gene (Rv0908) from Mycobacterium tuberculosis H37Rv. Radioactive transport assays revealed that CtpE is a Ca2+-specific transporter. Ca2+ deficiency increased expression of ctpE, resulting in increased 45Ca2+ accumulation in cells. ctpE is a gene that is part of an operon, which is negatively regulated by Ca2+. The ctpE mutant also showed hypersensitivity to polymyxin B, increased biofilm formation, and higher cell aggregation, indicating cell envelope defects. Our work establishes, for the first time, the presence of Ca2+ uptake pumps of the energy-dependent P-type ATPase superfamily in bacteria and also implicates that intracellular Ca2+ is essential for growth and cell envelope integrity in M. smegmatis.

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Section: Discussionmentioning

confidence: 99%

A Novel Calcium Uptake Transporter of Uncharacterized P-Type ATPase Family Supplies Calcium for Cell Surface Integrity in Mycobacterium smegmatis

Gupta

Shrivastava

Sharma

2017

mBio

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“…Although some of these proteins were shown to play important roles in virulence and host–pathogen interactions, their Ca 2+ binding and the mechanisms of action were not studied in detail (Table 3 ). For example, a CaM-like protein, CAMLP, in a human pathogen M. tuberculosis shown to activate Nicotinamide Adenine Dinucleotide (NAD) kinase and phosphodiesterase (PDE) 61 plays a role in M. tuberculosis growth and survival in macrophages 62 , 63 . Two CaM-like proteins in Bacillus subtilis include CALP, which stimulates PDE and NAD kinase in a Ca 2+ -dependent manner 64 and YtaF, suggested to activate Ca 2+ dependent proteins required for sporulation 65 .…”

Section: Discussionmentioning

confidence: 99%

EF-hand protein, EfhP, specifically binds Ca2+ and mediates Ca2+ regulation of virulence in a human pathogen Pseudomonas aeruginosa

Kayastha

Kubo

Burch-Konda

et al. 2022

Sci Rep

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Calcium (Ca2+) is well known as a second messenger in eukaryotes, where Ca2+ signaling controls life-sustaining cellular processes. Although bacteria produce the components required for Ca2+ signaling, little is known about the mechanisms of bacterial Ca2+ signaling. Previously, we have identified a putative Ca2+-binding protein EfhP (PA4107) with two canonical EF-hand motifs and reported that EfhP mediates Ca2+ regulation of virulence factors production and infectivity in Pseudomonas aeruginosa, a human pathogen causing life-threatening infections. Here, we show that EfhP selectively binds Ca2+ with 13.7 µM affinity, and that mutations at the +X and −Z positions within each or both EF-hand motifs abolished Ca2+ binding. We also show that the hydrophobicity of EfhP increased in a Ca2+-dependent manner, however no such response was detected in the mutated proteins. 15 N-NMR showed Ca2+-dependent chemical shifts in EfhP confirming Ca2+-binding triggered structural rearrangements in the protein. Deletion of efhP impaired P. aeruginosa survival in macrophages and virulence in vivo. Disabling EfhP Ca2+ binding abolished Ca2+ induction of pyocyanin production in vitro. These data confirm that EfhP selectively binds Ca2+, which triggers its structural changes required for the Ca2+ regulation of P. aeruginosa virulence, thus establishing the role of EfhP as a Ca2+ sensor.

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