Andrew Darwin Lab - Microbiology

Andrew Darwin Ph.D.

Associate Professor, Department of Microbiology

Medical Science Building, Room 202
550 First Avenue, New York NY 10016
Office: (212) 263-3223
Fax: (212) 263-8276
Lab: (212) 263-3224




Bacteriology, bacterial genetics, Yersinia, Pseudomonas, stress response, infectious disease, gene regulation, signal transduction, membrane proteins



Graduate Education:

Ph.D. (Biochemistry) in 1993, University of Birmingham, U.K.

Postdoctoral Training:

1993-1996 Cornell University 1996-2000 Washington University in St. Louis

Academic Appointments:

2001: Assistant Professor of Microbiology
2007: Associate Professor of Microbiology


Major Responsibilities:

Course director (Advanced Topics in Microbial Pathogenesis)

Major Honors:

Burroughs Wellcome Fund Investigator in the Pathogenesis of Infectious Diseases (2007)



My lab is interested in bacterial cell envelope functions that prevent or respond to cellular stress occurring as pathogens infect their hosts. We use genetics, molecular biology and biochemistry, along with various infection models, to study the human pathogens Yersinia enterocolitica and Pseudomonas aeruginosa. These and other bacterial pathogens export a variety of proteins to disable or modulate host cell functions. However, production of the required protein secretion machineries has the potential to cause significant stress within the bacterial cell envelope. We have focused on well-characterized secretion systems that share a specialized outer membrane pore-forming protein known as a secretin. These secretins can mislocalize within the cell envelope and cause an acute stress that quickly leads to cell death. Therefore, bacteria must prevent or respond to this potential injury in order to successfully infect a host. Our work suggests that Y. enterocolitica and P. aeruginosa have addressed this problem in different ways.

Yersinia enterocolitica: In Y. enterocolitica, a highly specialized stress response system is required to tolerate cell injury caused by secretins. This is something called the Phage-shock-protein (Psp) system, which is essential for virulence and is also conserved in many other medically important bacteria. Mutants with a defective Psp system are quickly killed if they synthesize a secretin protein, probably due to disruption of their cell envelope. We are interested in understanding signals that activate the Psp system, studying the Psp regulatory and signal transduction mechanisms, and investigating changes in bacterial physiology when the Psp system is active.

Pseudomonas aeruginosa: P. aeruginosa is a prolific protein secretor, and has multiple secretin-containing export systems. However, it does not have a Psp system to deal with the potential for secretin-induced cell injury. We are investigating why this is the case. Our work suggests that rather than having afunctional equivalent of the Psp stress response system, P. aeruginosa might actively prevent secretin-induced stress from occurring in the first place. We have isolated a collection of P. aeruginosa mutants that are hypersensitive to secretin protein production and are characterizing the functions of the inactivated genes. This project is revealing information about P. aeruginosa functions important for its cell envelope assembly, function and integrity.



The Pseudomonas aeruginosa periplasmic protease CtpA can affect systems that impact its ability to mount both acute and chronic infections
Seo J, Darwin AJ
Infect Immun. 2013 Dec;81(12):4561-70

Stress relief during host infection: the phage shock protein response supports bacterial virulence in various ways
Darwin AJ.
PLoS Pathog. 2013 Jul;9(7):e1003388.

Changes in Psp protein binding partners, localization and behaviour upon activation of the Yersinia enterocolitica phage shock protein response
Yamaguchi S, Reid DA, Rothenberg E, Darwin AJ.
Mol Microbiol. 2013 Feb;87(3):656-671.

Links between type III secretion and extracytoplasmic stress responses in Yersinia
Flores-Kim J, Darwin AJ
Front Cell Infect Microbiol. 2012; 2:125.

Phage shock protein C (PspC) of Yersinia enterocolitica is a polytopic membrane protein with implications for regulation of the Psp stress response
Flores-Kim J, Darwin AJ
J Bacteriol. 2012 Dec;194(23):6548-59.

Phage shock proteins B and C prevent lethal cytoplasmic membrane permeability in Yersinia enterocolitica
Horstman NK, Darwin AJ.
Mol Microbiol. 2012 Aug;85(3):445-60.

Stress response in the pathogenic Yersinia species
Horstman NK, Darwin AJ
In: Stress Response in Microbiology (JM Requena, ed.). June 2012, Horizon Scientific Press, United Kingdom.

Recent findings about the Yersinia enterocolitica phage shock protein response
Yamaguchi S, Darwin AJ
J Microbiol. 2012 Feb;50(1):1-7.

FtsH-dependent degradation of Phage Shock Protein C in Yersinia enterocolitica and Escherichia coli
Singh S, Darwin AJ.
J Bacteriol. 2011 Dec;193(23):6436-42.

The Yersinia enterocolitica Phage Shock Proteins B and C can form homodimers and heterodimers in vivo with the possibility of close association between multiple domains
Gueguen E, Flores-Kim J, Darwin AJ.
J Bacteriol. 2011 Oct;193(20):5747-58.

Membrane association of PspA depends on activation of the phage-shock-protein response in Yersinia enterocolitica
Yamaguchi S, Gueguen E, Horstman NK, Darwin AJ.
Mol Microbiol. 2010 Oct;78(2):429-43.

Analysis of the Yersinia enterocolitica PspBC proteins defines functional domains, essential amino acids and new roles within the phage-shock-protein response
Gueguen E, Savitzky DC, Darwin AJ.
Mol Microbiol. 2009 Nov;74(3):619-33. Epub 2009 Sep 22.

Analysis of secretin-induced stress in Pseudomonas aeruginosa suggests prevention rather than response and identifies a novel protein involved in secretin function
Seo J, Brencic A, Darwin AJ.
J Bacteriol. 2009 Feb;191(3):898-908.

YtxR acts as an overriding transcriptional off switch for the Yersinia enterocolitica Ysc-Yop type 3 secretion system
Axler-DiPerte GL, Hinchliffe SJ, Wren BW, Darwin AJ.
J Bacteriol. 2009 Jan;191(2):514-24.

Regulation of the phage-shock-protein stress response in Yersinia enterocolitica
Darwin AJ.
Adv Exp Med Biol. 2007;603:167-77.

Global analysis of tolerance to secretin-induced stress in Yersinia enterocolitica suggests that the phage-shock-protein system may be a remarkably self-contained stress response
Seo J, Savitzky DC, Ford E, Darwin AJ.
Mol Microbiol. 2007 Aug;65(3):714-27.

YtxR, a conserved LysR-like regulator that induces expression of genes encoding a putative ADP-ribosyltransferase toxin homologue in Yersinia enterocolitica
Axler-Diperte GL, Miller VL, Darwin AJ.
J Bacteriol. 2006 Dec;188(23):8033-43.

Multiple promoters control expression of the Yersinia enterocolitica phage-shock-protein A (pspA) operon
Maxson ME, Darwin AJ.
Microbiology. 2006 Apr;152(Pt 4):1001-10.

PspB and PspC of Yersinia enterocolitica are dual function proteins: regulators and effectors of the phage-shock-protein response
Maxson ME, Darwin AJ.
Mol Microbiol. 2006 Mar;59(5):1610-23.

Improved system for construction and analysis of single-copy beta-galactosidase operon fusions in Yersinia enterocolitica
Maxson ME, Darwin AJ.
Appl Environ Microbiol. 2005 Sep;71(9):5614-8.

Genome-wide screens to identify genes of human pathogenic Yersinia species that are expressed during host infection
Darwin AJ.
Curr Issues Mol Biol. 2005 Jul;7(2):135-49.

The phage-shock-protein response
Darwin AJ.
Mol Microbiol. 2005 Aug;57(3):621-8.

PspG, a new member of the Yersinia enterocolitica phage shock protein regulon
Green RC, Darwin AJ.
J Bacteriol. 2004 Aug;186(15):4910-20.

Identification of inducers of the Yersinia enterocolitica phage shock protein system and comparison to the regulation of the RpoE and Cpx extracytoplasmic stress responses
Maxson ME, Darwin AJ.
J Bacteriol. 2004 Jul;186(13):4199-208.



Josué Flores-Kim (Graduate Student)
Dana Harmon (Postdoctoral Fellow)
Jin Seo (Postdoctoral Fellow)
Reina Rau (Research Technician)



Ana Fiterman
Michelle Maxson, PhD
Rebecca Green, PhD
Diana Savitzky, MD
Grace Axler-DiPerte, PhD
Theodora Georgopoulos, MS
Terry Ann-Smith
Erwan Gueguen, PhD
Sindhoora Singh
Kaye Horstman, PhD
Saori Yamaguchi, PhD