Matthias Peter Machner, Ph.D.

Senior Investigator

Section of Microbial Pathogenesis


NIHBC 49 - Conte 1A35B


Research Topics

Host Cell Modulation by the Intracellular Pathogen Legionella pneumophila

Many Gram-negative bacteria manipulate host cell signaling or trafficking events in order to create an intracellular environment supportive of bacterial growth. One of those microbes is Legionella pneumophila, the causative agent of a life-threatening pneumonia called Legionnaires' disease. Upon phagocytosis by alveolar macrophages, L. pneumophila uses a type IV secretion system (T4SS) to deliver a large number of bacterial proteins, or effectors, into the host-cell cytosol (Fig. 1). Some of those effectors help L. pneumophila to redirect proteins and membrane material of the infected cell to its Legionella-containing vacuole (LCV), thereby establishing a protective compartment resembling host-cell endoplasmic reticulum (ER). L. pneumophila mutants with a non-functional T4SS are avirulent, underscoring the importance of the translocated effector proteins for L. pneumophila infection. The main focus of our laboratory is to identify and characterize host-pathogen interactions during L. pneumophila infection and to determine their importance for bacterial virulence.


Dr. Matthias P. Machner graduated from the German college Gymnasium Carolinum of Osnabrueck in 1991. He obtained his Diploma in Biology in 1998 after working with Dr. Hildgund Schrempf at the University of Osnabrueck. Dr. Machner received his Ph.D. degree in Life Sciences (Dr. rer. nat.) from the Carolo Wilhelmina University of Braunschweig, Germany in 2002, graduating with highest distinction (summa cum laude). He then moved to Boston, Massachusetts, where he pursued postdoctoral studies with Dr. Ralph R. Isberg at Tufts University School of Medicine. In 2008, Dr. Machner accepted a tenure-track investigator position in the Cell Biology and Metabolism Program as Head of the Unit on Microbial Pathogenesis which has been committed to deciphering the molecular mechanisms underlying Legionnaires’ disease, a severe pneumonia caused by the bacterium Legionella pneumophila. Since approval of his tenure in 2016, Dr. Machner’s has continued his work on L. pneumophila virulence strategies. His laboratory recently made the discovery that the human Hippo pathway, a conserved signaling route best known for its importance in tissue development as well as tumorigenesis, also plays an unexpected role during infection by L. pneumophila.

Selected Publications

  1. Ellis NA, Kim B, Tung J, Machner MP. A multiplex CRISPR interference tool for virulence gene interrogation in Legionella pneumophila. Commun Biol. 2021;4(1):157.

  2. Lee PC, Beyrakhova K, Xu C, Boniecki MT, Lee MH, Onu CJ, Grishin AM, Machner MP, Cygler M. The Legionella kinase LegK7 exploits the Hippo pathway scaffold protein MOB1A for allostery and substrate phosphorylation. Proc Natl Acad Sci U S A. 2020;117(25):14433-14443.

  3. Tascón I, Li X, Lucas M, Nelson D, Vidaurrazaga A, Lin YH, Rojas AL, Hierro A, Machner MP. Structural insight into the membrane targeting domain of the Legionella  deAMPylase SidD. PLoS Pathog. 2020;16(8):e1008734.

  4. Lee PC, Machner MP. The Legionella Effector Kinase LegK7 Hijacks the Host Hippo Pathway to Promote Infection. Cell Host Microbe. 2018;24(3):429-438.e6.

  5. Neunuebel MR, Chen Y, Gaspar AH, Backlund PS Jr, Yergey A, Machner MP. De-AMPylation of the small GTPase Rab1 by the pathogen Legionella pneumophila. Science. 2011;333(6041):453-6.

This page was last updated on November 1st, 2018