Surface anchoring of bacterial subtilisin important for maturation function.
Many extracytoplasmic proteins undergo proteolytic processing during secretion, which is essential to their maturation. These post-translational modifications are carried out by specific enzymes whose subcellular localization is important for function. We have described a maturation subtilisin in Gram-negative Bordetella pertussis, the autotransporter SphB1. SphB1 catalyses the maturation of the precursor of the adhesin filamentous haemagglutinin (FHA) at the bacterial surface, in addition to the processing of its own precursor. Here, we show that the outer membrane anchor of SphB1 is crucial to its function, as evidenced by the lack of FHA maturation in a strain releasing a variant of SphB1 into the milieu. In contrast, surface association is not required for automaturation of SphB1. The surface retention of mature SphB1 is mediated by lipidation of the protein. The tethered protease appears to be stabilized by unusual Gly- and Pro-rich motifs at the N-terminus of the protein. This represents a new mode of localization for a protease involved in protein secretion.
Coutte
Loic
L
INSERM U44, Institut de Biologie de Lille, Institut Pasteur de Lille, 1 rue Calmette, 59019 Lille Cedex, France.
Willery
Eve
E
Antoine
Rudy
R
Drobecq
Hervé
H
Locht
Camille
C
Jacob-Dubuisson
Françoise
F
D018829:Adhesins, Bacterial / Q000378:metabolism*; D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001886:Bordetella pertussis / Q000502:physiology; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D006388:Hemagglutinins / Q000378:metabolism*; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D010566:Virulence Factors, Bordetella / Q000378:metabolism*
D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D017261:Glycosylphosphatidylinositols; D006388:Hemagglutinins; D010566:Virulence Factors, Bordetella; C065273:filamentous hemagglutinin adhesin, Bordetella pertussis; D012697:Serine Endopeptidases; C437318:SphB1 protein, Bordetella pertussis