Role of group A Streptococcus HtrA in the maturation of SpeB protease.
The serine protease high-temperature requirement A (HtrA) (DegP) of the human pathogen Streptococcus pyogenes (group A Streptococcus; GAS) is localized to the ExPortal secretory microdomain and is reportedly essential for the maturation of cysteine protease streptococcal pyrogenic exotoxin B (SpeB). Here, we utilize HSC5 (M5 serotype) and the in-frame isogenic mutant HSC5DeltahtrA to determine whether HtrA contributes to the maturation of other GAS virulence determinants. Mutanolysin cell wall extracts and secreted proteins were arrayed by 2-DE and identified by MALDI-TOF PMF analysis. HSC5DeltahtrA had elevated levels of cell wall-associated M protein, whilst the supernatant had higher concentrations of M protein fragments and a reduced amount of mature SpeB protease, compared to wild-type (WT). Western blot analysis and protease assays revealed a delay in the maturation of SpeB in the HSC5DeltahtrA supernatant. HtrA was unable to directly process SpeB zymogen (proSpeB) to the active form in vitro. We therefore conclude that HtrA plays an indirect role in the maturation of cysteine protease SpeB.
Cole
Jason N
JN
School of Biological Sciences, University of Wollongong, Wollongong, New South Wales, Australia.
Aquilina
John A
JA
Hains
Peter G
PG
Henningham
Anna
A
Sriprakash
Kadaba S
KS
Caparon
Michael G
MG
Nizet
Victor
V
Kotb
Malak
M
Cordwell
Stuart J
SJ
Djordjevic
Steven P
SP
Walker
Mark J
MJ
D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D002473:Cell Wall / Q000737:chemistry; D003470:Culture Media; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000378:metabolism; D007700:Kinetics; D020543:Proteome; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013297:Streptococcus pyogenes / Q000201:enzymology*; D013997:Time Factors
D001426:Bacterial Proteins; D003470:Culture Media; D004792:Enzyme Precursors; D020543:Proteome; D003546:Cysteine Endopeptidases; C042477:streptopain