Morphogenic Protein RodZ Interacts with Sporulation Specific SpoIIE in Bacillus subtilis

Abstract

The first landmark in sporulation of Bacillus subtilis is the formation of an asymmetric septum followed by selective activation of the transcription factor σF in the resulting smaller cell. How the morphological transformations that occur during sporulation are coupled to cell-specific activation of transcription is largely unknown. The membrane protein SpoIIE is a constituent of the asymmetric sporulation septum and is a crucial determinant of σF activation. Here we report that the morphogenic protein, RodZ, which is essential for cell shape determination, is additionally required for asymmetric septum formation and sporulation. In cells depleted of RodZ, formation of asymmetric septa is disturbed and σF activation is perturbed. During sporulation, we found that SpoIIE recruits RodZ to the asymmetric septum. Moreover, we detected a direct interaction between SpoIIE and RodZ in vitro and in vivo, indicating that SpoIIE-RodZ may form a complex to coordinate asymmetric septum formation and σF activation. We propose that RodZ could provide a link between the cell shape machinery and the coordinated morphological and developmental transitions required to form a resistant spore.

A Novel Cell Type Enables B. subtilis to Escape from Unsuccessful Sporulation in Minimal Medium

“…The literature suggests that SpoIIE may regulate cell wall synthesis at the asymmetric division sites (Piggot and Coote, 1976; Illing and Errington, 1991; Barák and Youngman, 1996) and may play a role in peptidoglycan remodeling during engulfment (Campo et al, 2008). Indeed, a recent study indicated that SpoIIE recruits the morphogenic protein RodZ at the asymmetric septum during sporulation where both proteins might be involved in peptidoglycan thinning during engulfment (Muchova et al, 2016). The second distinct function of SpoIIE during sporulation is the activation of σ F in the forespore due to its phosphatase activity (Duncan et al, 1995; Arigoni et al, 1996; Feucht et al, 1996).…”

Stoichiometry and Mobility Switching of a Morphogenetic Protein in Live Differentiating Cells

“…This observation supports a model in which SpoIIE interacts with other proteins or complexes. In stage II i interactions would be with components of the divisome (12)(13)(14) while in stage II iii they would be with SpoIIQ, the forespore component of an intercellular channel formed with proteins encoded on the spoIIIA operon expressed in the mother cell (15).…”

“…Gene cloning in B. subtilis, unless specified, was performed using standard protocols (53) ( Table S1). To construct pSGIIE-mGFP, we used previously prepared pSGIIE-YPet (13). A PCR fragment containing mGFP was prepared using mGFPKpnF: (53) supplemented with chloramphenicol (5µg ml -1 ), erythromycin (1µg ml -1 ) and lincomycin (25µg ml -1 ) as required.…”

“…After closure of the sporulation septum, FtsZ disassembles. SpoIIE-mediated activation of  F correlates with release of SpoIIE from the sporulation septum, marking stage II ii (13). During stage II iii , SpoIIE interacts with SpoIIQ (15) the forespore component of an intercellular channel (16)(17)(18), crucial for later activation of  G .…”

“…Assembly of SpoIIE to form polar E-rings, dependent on FtsZ interactions (12), occurs during stage I, defined by formation of an axial filament spanning the cell length and comprising two copies of the chromosome each tethered through its origin region to a pole. Formation of the asymmetric septum is defined as stage II i , during which SpoIIE interacts with the divisome components RodZ (13) and DivIVA (14). After closure of the sporulation septum, FtsZ disassembles.…”