PI: Beth Lazazzera
Office Phone: 310-794-4804
Lab Phone: (310)794-4986
Office: Molecular Sciences 4610B
Lab: Molecular Sciences 4550-4560
Cell-cell signaling is a fundamental process carried out by all cell types. Bacteria communicate with each other to coordinate such processes development, antibiotic production, and virulence. We are studying the mechanism of cell-cell signaling in the model gram-positive bacterium, Bacillus subtilis. B. subtilis and other gram-positive bacteria use extracellular signaling peptides to communicate with each other.
B. subtilis secretes signaling peptides into the extracellular medium to serve as monitors of cell density. By studying the mechanism of sensing these signaling peptides, we have identified a new mechanism for signaling by a peptide. In contrast to other signaling peptides that are sensed through membrane receptors, the peptide, CSF, is actively transported into the cell where it functions intracellularly to bind to receptor proteins and regulate gene expression. The CSF peptide is also interesting because it has at least three targets inside the cell, which allows it to regulate two different developmental pathways at different concentrations of the peptide. We are currently taking genetic and biochemical approaches to determine the identity of the intracellular receptors of CSF and the mechanism of producing this small, unmodified peptide.
Bacterial biofilms are a structured community of cells enclosed in a self-produced polymeric matrix and adherent to an inert or living surface. Biofilms are the prevailing state of bacteria in nature and have a significant impact in clinical settings. We are using B. subtilis as a model organism to understand the molecular basis of biofilm formation by Gram-positive bacteria. We have identified several transcription factors that control biofilm formation. Through a combination of genetics and DNA microarray analysis, we are identifying genes regulated by these transcription factors that are contribute to biofilm formation.
The image below shows confocal scanning laser microscopy of biofilms formed by B. subtilis
Stanley NR, Lazazzera BA.
Environmental signals and regulatory pathways that influence biofilm formation.
Mol Microbiol. 2004 May;52(4):917-24.
Hamon MA, Stanley NR, Britton RA, Grossman AD, Lazazzera BA.
Identification of AbrB-regulated genes involved in biofilm formation by Bacillus subtilis.
Mol Microbiol. 2004 May;52(3):847-60.
Stanley NR, Britton RA, Grossman AD, Lazazzera BA.
Identification of catabolite repression as a physiological regulator of biofilm formation by Bacillus subtilis by use of DNA microarrays.
J Bacteriol. 2003 Mar;185(6):1951-7.
Pottathil M, Lazazzera BA.
The extracellular Phr peptide-Rap phosphatase signaling circuit of Bacillus subtilis.
Front Biosci. 2003 Jan 1;8:d32-45. Review.
Hamon MA, Lazazzera BA.
The sporulation transcription factor Spo0A is required for biofilm development in Bacillus subtilis.
Mol Microbiol. 2001 Dec;42(5):1199-209.
The intracellular function of extracellular signaling peptides.
Peptides. 2001 Oct;22(10):1519-27. Review.
Quorum sensing and starvation: signals for entry into stationary phase.
Curr Opin Microbiol. 2000 Apr;3(2):177-82. Review.
Lazazzera BA, Kurtser IG,
McQuade RS, Grossman AD.
An autoregulatory circuit affecting peptide signaling in Bacillus subtilis.
J Bacteriol. 1999 Sep;181(17):5193-200.
Lazazzera BA, Grossman AD.
The ins and outs of peptide signaling.
Trends Microbiol. 1998 Jul;6(7):288-94. Review.
Geraldine Briceno – Staff Research Associate
Nathalia Cota – Graduate Student
Melanie Hamon – Graduate
Sara Lanigan – Graduate Student
Mridula Pottathil – Graduate Student
Becky Terra – Graduate Student
Nicola Stanley, Ph.D. – Postdoctoral Fellow
Lazazzera Lab Photographs