Identification and biochemical characterization of a eukaryotic-type serine/threonine kinase and its cognate phosphatase in Streptococcus pyogenes: their biological functions and substrate identification.
A eukaryotic-type signaling system in group A Streptococcus (GAS) was identified and characterized. This system comprises primarily the products of two co-transcribed genes, a eukaryotic-type Ser/Thr kinase (SP-STK) and phosphatase (SP-STP) and their endogenous substrate histone-like protein (SP-HLP). Enzyme activities of SP-STK and SP-STP primarily depended on Mn(2+). The site on the substrate for reversible phosphorylation by these enzymes was found to be only the threonine residue. Using specific antibodies generated against these proteins, SP-STK was found to be membrane-associated with its N-terminal kinase domain facing the cytoplasm and its C-terminal repeat domain outside the membrane and cell-wall associated. Further, SP-STP, primarily a cytoplasmic protein, was found to be a major secretory protein of GAS and essential for bacterial survival. Three isogenic mutants, lacking either the entire SP-STK, or one of its two domains, were found displaying distinct pleiotropic effects on growth, colony morphology, cell division/septation, surface protein/virulence factor expression, bacterial ability to adhere to and invade human pharyngeal cells, and resist phagocytosis by human neutrophils. In addition to these properties, the ability of these three proteins to modulate the expression of the major virulence factors, the M protein and the capsule, indicates that these proteins are structurally and functionally distinct from the kinases and phosphatases described in other microorganisms and play a key role in GAS pathogenesis.
Laboratory of Bacterial Pathogenesis, Department of Pathology, Ohio State University College of Medicine and Public Health, 288A, Tzgournis Medical Research Facility, 420 W 12th Avenue, Columbus, OH 43210-1214, USA.
Hong
H
Jin
Vijay
V
Pancholi
D000595:Amino Acid Sequence; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D048430:Cell Shape; D006801:Humans; D008969:Molecular Sequence Data; D010587:Phagocytosis; D010614:Pharynx / Q000166:cytology / Q000382:microbiology; D010749:Phosphoprotein Phosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D015398:Signal Transduction / Q000502:physiology*; D013297:Streptococcus pyogenes / Q000166:cytology / Q000201:enzymology* / Q000235:genetics; D013379:Substrate Specificity; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D017346:Protein Serine-Threonine Kinases; D010749:Phosphoprotein Phosphatases