ArticlePLoS biology2022
The Mycobacterium tuberculosis PE15/PPE20 complex transports calcium across the outer membrane.
Article in PLoS biology, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 30 papers.
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Who cites it
30 citing papers in PubMed, 41 citations in OpenAlex.
- The mycomembrane proteins PorH and ProtX are inserted at polar growth zones and linked to the cell wall.Proceedings of the National Academy of Sciences of the United States of America · 2026Article
- Variation in multiple classes of simple sequence repeats can alter drug susceptibility inbioRxiv : the preprint server for biology · 2026Article
- The calcium signal regulatory network and the roles of calcium-binding proteins in bacteria.World journal of microbiology & biotechnology · 2026Review
- Mycobacterium tuberculosis VadK is required for the regulation of the methylcitrate cycle and virulence.EMBO reports · 2026Article
- Article
- PE/PPE proteins contribute to Mycobacterium tuberculosis drug resistance.Nature communications · 2026Article
- Membrane-associated effluxosomes coordinate multi-metal resistance in Mycobacterium tuberculosis.The EMBO journal · 2026Article
- ThemBio · 2026Article
- Article
- Recent Characterization of Key Proteins to Combat Tuberculosis.Advances in experimental medicine and biology · 2026Review
- Retro-inversion imparts antimycobacterial specificity to host defense peptides.Nature communications · 2025Article
- Article
- Mycobacterium tuberculosis uses intrinsically disordered, fast evolving proteins to interact with conserved host factors.Genome biology · 2025Article
- Control of Mycobacterium tuberculosis protein secretion by ESX-4 and the outer membrane EsxUT-EsxEF complex.Nature communications · 2025Article
- PPE51 modulates membrane integrity inmBio · 2025Article
- Immunopeptidomics can inform the design of mRNA vaccines for the delivery ofScience translational medicine · 2025Article
- VadK, a Non-Canonical Kinase that Regulates the Methylcitrate Cycle and is Essential forbioRxiv : the preprint server for biology · 2025Article
- AnaToc75 (Alr2269) mediates calcium uptake across the outer membrane inJournal of bacteriology · 2025Article
- Ongoing evolution of PE/PPE genes inmSystems · 2025Article
- Targeting infection-specific peptides in immunopeptidomics studies for vaccine target discovery.The Journal of experimental medicine · 2025Article
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Authors and funding
3 authors at 1 institution in 1 country.
Funding
Abstract
The mechanisms by which nutrients traverse the Mycobacterium tuberculosis (Mtb) outer membrane remain mostly unknown and, in the absence of classical porins, likely involve specialized transport systems. Calcium ions (Ca2+) are an important nutrient and serve as a second messenger in eukaryotes, but whether bacteria have similar Ca2+ signaling systems is not well understood. To understand the basis for Ca2+ transport and signaling in Mtb, we determined Mtb's transcriptional response to Ca2+. Overall, only few genes changed expression, suggesting a limited role of Ca2+ as a transcriptional regulator. However, 2 of the most strongly down-regulated genes were the pe15 and ppe20 genes that code for members of a large family of proteins that localize to the outer membrane and comprise many intrinsically disordered proteins. PE15 and PPE20 formed a complex and PPE20 directly bound Ca2+. Ca2+-associated phenotypes such as increased ATP consumption and biofilm formation were reversed in a pe15/ppe20 knockout (KO) strain, suggesting a direct role in Ca2+ homeostasis. To test whether the PE15/PPE20 complex has a role in Ca2+ transport across the outer membrane, we created a fluorescence resonance energy transfer (FRET)-based Ca2+ reporter strain. A pe15/ppe20 KO in the FRET background showed a specific and selective loss of Ca2+ influx that was dependent on the presence of an intact outer cell wall. These data show that PE15/PPE20 form a Ca2+-binding protein complex that selectively imports Ca2+, show a distinct transport function for an intrinsically disordered protein, and support the emerging idea of a general family-wide role of PE/PPE proteins as idiosyncratic transporters across the outer membrane.
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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.