Staphylococcus aureusFtsZ and PBP4 bind to the conformationally dynamic N-terminal domain of GpsB

Abstract

Bacterial cell division is a tightly regulated process that requires the formation of a dynamic multi-protein complex. In the Firmicutes phylum, GpsB is a membrane associated protein that coordinates peptidoglycan synthesis for cell growth and division. Although GpsB has been studied in several organisms, the structure, function, and interactome of Staphylococcus aureus GpsB is largely uncharacterized, despite being reported as uniquely essential for growth in this clinically relevant bacterium. To address this knowledge gap, we solved the crystal structure of the N-terminal domain of S. aureus GpsB. This structure reveals an atypical asymmetric dimer, and major conformational flexibility that can be mapped to a hinge region formed by a three-residue insertion exclusive to Staphylococci. When this three-residue insertion is excised, its thermal stability increases, and the mutant no longer produces a previously reported lethal phenotype when overexpressed in Bacillus subtilis. Furthermore, we provide the first biochemical, biophysical, and crystallographic evidence that the N-terminal domain of GpsB binds not only PBP4, but also FtsZ, through a conserved recognition motif located on their C-terminus, thus linking peptidoglycan synthesis with cell division. Taken together, the unique structure of S. aureus GpsB and its direct interaction with FtsZ/PBP4 provide deeper insight into the central role of GpsB in S. aureus cell division.

The cell cycle of Staphylococcus aureus: An updated review

“…pneumoniae (Claessen et al, 2008;Land et al, 2013;Rismondo et al, 2016;Sacco et al, 2022;Tavares et al, 2008). However, in S.…”

“…All the proteins constituting the divisome either have an active role in the synthesis of new PG or in coordinating these processes with cell division (Booth & Lewis, 2019 ; Pinho et al, 2013 ). For example, GpsB, a protein conserved within the Firmicutes phylum, has been shown to coordinate PG synthase activity with other cell division processes by interacting with PBPs in B. subtilis , Listeria monocytogenes , and S. pneumoniae (Claessen et al, 2008 ; Land et al, 2013 ; Rismondo et al, 2016 ; Sacco et al, 2022 ; Tavares et al, 2008 ). However, in S. aureus GpsB appears to modulate and stabilize Z ring assembly and contribute to the remodeling of the divisiome by interacting with FtsZ (Eswara et al, 2018 ; Sacco et al, 2022 ).…”

“…For example, GpsB, a protein conserved within the Firmicutes phylum, has been shown to coordinate PG synthase activity with other cell division processes by interacting with PBPs in B. subtilis , Listeria monocytogenes , and S. pneumoniae (Claessen et al, 2008 ; Land et al, 2013 ; Rismondo et al, 2016 ; Sacco et al, 2022 ; Tavares et al, 2008 ). However, in S. aureus GpsB appears to modulate and stabilize Z ring assembly and contribute to the remodeling of the divisiome by interacting with FtsZ (Eswara et al, 2018 ; Sacco et al, 2022 ). A recent study by Hammond et al ( 2022 ) found that S. aureus GpsB directly interacts with TarG, a component of the ABC transporter that exports WTA to the cell surface, thereby coordinating the WTA synthesis machinery with the divisome complex.…”

“…aureus GpsB appears to modulate and stabilize Z ring assembly and contribute to the remodeling of the divisiome by interacting with FtsZ (Eswara et al, 2018;Sacco et al, 2022). A recent study by Hammond et al (2022) found that S. aureus GpsB directly interacts with TarG, a component of the ABC transporter that exports WTA to the cell surface, thereby coordinating the WTA synthesis machinery with the divisome complex.…”

Chromosomal Duplications of MurZ (MurA2) or MurA (MurA1), Amino Acid Substitutions in MurZ (MurA2), and Absence of KhpAB Obviate the Requirement for Protein Phosphorylation inStreptococcus pneumoniaeD39

“…Combined studies indicate that GpsB plays species-specific roles in regulating PG synthesis (Cleverley et al ., 2019, Hammond et al ., 2019). Based on genetic and biochemical studies, one role shared by GpsB in different bacteria is as an adaptor that docks PG synthases to other cell-wall enzymes and scaffold proteins to form complexes for division and septal and lateral PG synthesis (Rued et al ., 2017, Cleverley et al ., 2019, Halbedel & Lewis, 2019, Sacco et al ., 2022). Binding between GpsB homologs and Class A PBPs, including PBP1( Bsu ), PBPA1( Lmo ), and aPBP2a( Spn ) and Class C PBP4( Sau ) occurs by a conserved mechanism, wherein Arg residues in amino-terminal, cytoplasmic microdomains of the PBPs bind to a specific site in the amino-terminal domain of GpsB (Cleverley et al ., 2019, Sacco et al ., 2022).…”