A Family of Spore Lipoproteins Stabilizes the Germination Apparatus by Altering Inner Spore Membrane Fluidity in Bacillus subtilis Spores

Flores, Matthew J.; Duricy, Kate; Choudhary, Shreya; Laue, Michael; Popham, David L.

doi:10.1128/jb.00142-23

Cited by 6 publications

(1 citation statement)

References 57 publications

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“…It is possible that lipid binding by FigP could function as the trigger for channel opening. If this model is correct, the activating lipids would have to be kept away from the 5AF/FigP oligomers during spore formation and dormancy and would only access the complexes after the onset of germination, perhaps due to changes in membrane fluidity ( Cowan et al 2003 ; Flores et al 2023 ). Alternatively, we speculate that changes in membrane voltage due to ion release by GerA family receptors are transduced through the lipid–FigP interaction.…”

Section: Discussionmentioning

confidence: 99%

SpoVAF and FigP assemble into oligomeric ion channels that enhance spore germination

Gao,

Amon,

Brogan

et al. 2024

Genes Dev.

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Bacterial spores can remain dormant for decades yet rapidly germinate and resume growth in response to nutrients. GerA family receptors that sense and respond to these signals have recently been shown to oligomerize into nutrient-gated ion channels. Ion release initiates exit from dormancy. Here, we report that a distinct ion channel, composed of SpoVAF (5AF) and its newly discovered partner protein, YqhR (FigP), amplifies the response. At high germinant concentrations, 5AF/FigP accelerate germination; at low concentrations, this complex becomes critical for exit from dormancy. 5AF is homologous to the channel-forming subunit of GerA family receptors and is predicted to oligomerize around a central pore.5AFmutations predicted to widen the channel cause constitutive germination during spore formation and membrane depolarization in vegetative cells. Narrow-channel mutants are impaired in germination. A screen for suppressors of a constitutively germinating 5AF mutant identified FigP as an essential cofactor of 5AF activity. We demonstrate that 5AF and FigP interact and colocalize with GerA family receptors in spores. Finally, we show that 5AF/FigP accelerate germination inB. subtilisspores that have nutrient receptors from another species. Our data support a model in which nutrient-triggered ion release by GerA family receptors activates 5AF/FigP ion release, amplifying the response to germinant signals.

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Section: Discussionmentioning

confidence: 99%