The interferon-γ (IFN-γ)-inducible immunity-related GTPase (IRG), Irgm1, plays an essential role in restraining activation of the IRG pathogen resistance system. However, the loss of Irgm1 in mice also causes a dramatic but unexplained susceptibility phenotype upon infection with a variety of pathogens, including many not normally controlled by the IRG system. This phenotype is associated with lymphopenia, hemopoietic collapse, and death of the mouse.Deutscher Akademischer Austausch Dienst (DAAD); International Graduate School in Development Health
and Disease (IGS-DHD); Deutsche For-schungsgemeinschaft (SFBs 635, 670, 680); Max-Planck-Gesellschaft (Max Planck Fellowship)

A Bafica

A Khaminets

AK Haldar

AV Terskikh

B Liu

BA Butcher

C Bekpen

C Wang

CG Feng

CL Vazquez

CM Collazo

CP Chang

D Degrandi

DE Nelson

E Kravets

F Ferreira-da-Silva Mda

F Kaiser

GA Taylor

H Mizuta

H Xu

HC Santiago

HH Pua

HM Springer

I Miyairi

J Coers

J Lilue

J Spandl

J. Bernd Helms

JD MacMicking

Jelena Maric-Biresev

Jonathan C. Howard

JP Hunn

Julia P. Hunn

KY King

L Bougneres

MG Gutierrez

MK Traver

N Papic

N Pawlowski

O Liesenfeld

Oleg Krut

P Boya

S He

S Martens

S Tiwari

Sascha Martens

SB Singh

SC Henry

T Uchimoto

TA Venezia

U Boehm

V Deretic

W Jia

Y Feng

YM Ling

YO Zhao

BMC Biology

PubMed

Maric-Biresev, Jelena

Hunn, Julia P.

Krut, Oleg

Helms, J. Bernd

Martens, Sascha

Howard, Jonathan C.

ARCA  Gulbenkian Institute of Science Repository

Loss of the interferon-γ-inducible regulatory immunity-related GTPase (IRG), Irgm1, causes activation of effector IRG proteins on lysosomes, damaging lysosomal function and predicting the dramatic susceptibility of Irgm1-deficient mice to infection

Number of autophagosomes is increased in IFN-γ-induced Irgm1 −/− cells. A Wild type and Irgm1 −/− mouse embryonic fibroblasts were induced with 200 U/mL IFN-γ for 24 hours and/or 40 μg/mL rapamycin for 2 hours, or left untreated. Cells were fixed and stained for LC3. Representative microscopic images of LC3 punctae and phase contrast are shown. Scale bars represent 10 μm. B Quantification of S7A, showing average number of LC3 punctae per cell. 50 cells per sample were counted and the results of two independent experiments are shown. (TIF 7475 kb

Jelena Maric-Biresev (3399923)

Julia Hunn (3399926)

Oleg Krut (3399929)

J. Helms (3399932)

Sascha Martens (46289)

Jonathan Howard (312009)

The Francis Crick Institute

Additional file 7: Figure S7. of Loss of the interferon-γ-inducible regulatory immunity-related GTPase (IRG), Irgm1, causes activation of effector IRG proteins on lysosomes, damaging lysosomal function and predicting the dramatic susceptibility of Irgm1-deficient mice to infection

Maric-Biresev, J.

Hunn, J.

Krut, O.

Helms, J.

Martens, S.

Howard, J.

MPG.PuRe

English

Loss of the interferon-gamma-inducible regulatory immunity-related GTPase (IRG), Irgm1, causes activation of effector IRG proteins on lysosomes, damaging lysosomal function and predicting the dramatic susceptibility of Irgm1-deficient mice to infection

Crossref

Irga6 does not co-localize with the Golgi in GMS-deficient cells. A Wild type, Irgm1 −/−, Irgm3 −/−, and Irgm1/Irgm3 −/− mouse embryonic fibroblasts were induced with 200 U/mL IFN-γ for 24 hours. Cells were fixed and stained for Irga6 (165/3) and for Golgi marker GM130. Representative microscopic images of Irga6 and Golgi co-localization are shown. Arrows point at the Irga6 structures magnified at the end of each panel in the following array: upper left: Irga6, upper right: GM130, lower left: merge. Scale bars represent 10 μM. B Quantification of S5A, showing percent of Irga6 structures co-localizing with GM130. 50 cells per sample were quantified. (TIF 8669 kb

Additional file 5: Figure S5. of Loss of the interferon-γ-inducible regulatory immunity-related GTPase (IRG), Irgm1, causes activation of effector IRG proteins on lysosomes, damaging lysosomal function and predicting the dramatic susceptibility of Irgm1-deficient mice to infection

LC3 co-localizes with LAMP1 in IFN-γ-induced Irgm1 −/− cells. Wild type (WT) and Irgm1 −/− mouse embryonic fibroblasts (MEFs) were induced with 200 U/mL IFN-γ for 24 hours, 40 μg/mL rapamycin for 2 hours, or left untreated. Cells were fixed and stained for LC3 and LAMP1. Representative microscopic images of LC3 and LAMP1 localization in WT and Irgm1 −/− MEFs are shown. Arrows point at the LC3 structures magnified at the end of each panel in the following array: upper left: LC3, upper right: LAMP1, lower left: merge, lower right: phase contrast. Scale bars represent 10 μM. (TIF 9874 kb

Additional file 8: Figure S8 of Loss of the interferon-γ-inducible regulatory immunity-related GTPase (IRG), Irgm1, causes activation of effector IRG proteins on lysosomes, damaging lysosomal function and predicting the dramatic susceptibility of Irgm1-deficient mice to infection

Springer - Publisher Connector

Background: The interferon-gamma (IFN-gamma)-inducible immunity-related GTPase (IRG), Irgm1, plays an essential role in restraining activation of the IRG pathogen resistance system. However, the loss of Irgm1 in mice also causes a dramatic but unexplained susceptibility phenotype upon infection with a variety of pathogens, including many not normally controlled by the IRG system. This phenotype is associated with lymphopenia, hemopoietic collapse, and death of the mouse. Results: We show that the three regulatory IRG proteins (GMS sub-family), including Irgm1, each of which localizes to distinct sets of endocellular membranes, play an important role during the cellular response to IFN-gamma, each protecting specific membranes from off-target activation of effector IRG proteins (GKS sub-family). In the absence of Irgm1, which is localized mainly at lysosomal and Golgi membranes, activated GKS proteins load onto lysosomes, and are associated with reduced lysosomal acidity and failure to process autophagosomes. Another GMS protein, Irgm3, is localized to endoplasmic reticulum (ER) membranes; in the Irgm3-deficient mouse, activated GKS proteins are found at the ER. The Irgm3-deficient mouse does not show the drastic phenotype of the Irgm1 mouse. In the Irgm1/Irgm3 double knock-out mouse, activated GKS proteins associate with lipid droplets, but not with lysosomes, and the Irgm1/Irgm3(-/-) does not have the generalized immunodeficiency phenotype expected from its Irgm1 deficiency. Conclusions: The membrane targeting properties of the three GMS proteins to specific endocellular membranes prevent accumulation of activated GKS protein effectors on the corresponding membranes and thus enable GKS proteins to distinguish organellar cellular membranes from the membranes of pathogen vacuoles. Our data suggest that the generalized lymphomyeloid collapse that occurs in Irgm1(-/-) mice upon infection with a variety of pathogens may be due to lysosomal damage caused by off-target activation of GKS proteins on lysosomal membranes and consequent failure of autophagosomal processing

Kölner UniversitätsPublikationsServer

Loss of the interferon-γ-inducible regulatory immunity-related GTPase (IRG), Irgm1, causes activation of effector IRG proteins on lysosomes, damaging lysosomal function and predicting the dramatic susceptibility of Irgm1-deficient mice to infection

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ARCA Gulbenkian Institute of Science Repository

The Francis Crick Institute

MPG.PuRe

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The Francis Crick Institute

The Francis Crick Institute

Springer - Publisher Connector

Kölner UniversitätsPublikationsServer