IQGAP1 Is Important for Activation of Caspase-1 in Macrophages and Is Targeted by <named-content content-type="genus-species">Yersinia pestis</named-content> Type III Effector YopM

ABSTRACT YopM is a leucine-rich repeat (LRR)-containing effector in several Yersinia species, including Yersinia pestis and Y. pseudotuberculosis. Different Yersinia strains encode distinct YopM isoforms with variable numbers of LRRs but conserved C-terminal tails. A 15-LRR isoform in Y. pseudotuber...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Lawton K. Chung, Naomi H. Philip, Valentina A. Schmidt, Antonius Koller, Till Strowig, Richard A. Flavell, Igor E. Brodsky, James B. Bliska
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2014
Materias:	Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/b52107ccd381415e9be79f32f4afdd51
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:b52107ccd381415e9be79f32f4afdd51
record_format	dspace
spelling	oai:doaj.org-article:b52107ccd381415e9be79f32f4afdd512021-11-15T15:47:22ZIQGAP1 Is Important for Activation of Caspase-1 in Macrophages and Is Targeted by <named-content content-type="genus-species">Yersinia pestis</named-content> Type III Effector YopM10.1128/mBio.01402-142150-7511https://doaj.org/article/b52107ccd381415e9be79f32f4afdd512014-08-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.01402-14https://doaj.org/toc/2150-7511ABSTRACT YopM is a leucine-rich repeat (LRR)-containing effector in several Yersinia species, including Yersinia pestis and Y. pseudotuberculosis. Different Yersinia strains encode distinct YopM isoforms with variable numbers of LRRs but conserved C-terminal tails. A 15-LRR isoform in Y. pseudotuberculosis YPIII was recently shown to bind and inhibit caspase-1 via a YLTD motif in LRR 10, and attenuation of YopM− YPIII was reversed in mice lacking caspase-1, indicating that caspase-1 inhibition is a major virulence function of YopMYPIII. To determine if other YopM proteins inhibit caspase-1, we utilized Y. pseudotuberculosis strains natively expressing a 21-LRR isoform lacking the YLTD motif (YopM32777) or ectopically expressing a Y. pestis 15-LRR version with a functional (YopMKIM) or inactivated (YopMKIM D271A) YLTD motif. Results of mouse and macrophage infections with these strains showed that YopM32777, YopMKIM, and YopMKIM D271A inhibit caspase-1 activation, indicating that the YLTD motif is dispensable for this activity. Analysis of YopMKIM deletion variants revealed that LRRs 6 to 15 and the C-terminal tail are required to inhibit caspase-1 activation. YopM32777, YopMKIM, and YopMKIM deletion variants were purified, and binding partners in macrophage lysates were identified. Caspase-1 bound to YopMKIM but not YopM32777. Additionally, YopMKIM bound IQGAP1 and the use of Iqgap1−/− macrophages revealed that this scaffolding protein is important for caspase-1 activation upon infection with YopM− Y. pseudotuberculosis. Thus, while multiple YopM isoforms inhibit caspase-1 activation, their variable LRR domains bind different host proteins to perform this function and the LRRs of YopMKIM target IQGAP1, a novel regulator of caspase-1, in macrophages. IMPORTANCE Activation of caspase-1, mediated by macromolecular complexes termed inflammasomes, is important for innate immune defense against pathogens. Pathogens can, in turn, subvert caspase-1-dependent responses through the action of effector proteins. For example, the Yersinia effector YopM inhibits caspase-1 activation by arresting inflammasome formation. This caspase-1 inhibitory activity has been studied in a specific YopM isoform, and in this case, the protein was shown to act as a pseudosubstrate to bind and inhibit caspase-1. Different Yersinia strains encode distinct YopM isoforms, many of which lack the pseudosubstrate motif. We studied additional isoforms and found that these YopM proteins inhibit caspase-1 activation independently of a pseudosubstrate motif. We also identified IQGAP1 as a novel binding partner of the Yersinia pestis YopMKIM isoform and demonstrated that IQGAP1 is important for caspase-1 activation in macrophages infected with Yersinia. Thus, this study reveals new insights into inflammasome regulation during Yersinia infection.Lawton K. ChungNaomi H. PhilipValentina A. SchmidtAntonius KollerTill StrowigRichard A. FlavellIgor E. BrodskyJames B. BliskaAmerican Society for MicrobiologyarticleMicrobiologyQR1-502ENmBio, Vol 5, Iss 4 (2014)
institution	DOAJ
collection	DOAJ
language	EN
topic	Microbiology QR1-502
spellingShingle	Microbiology QR1-502 Lawton K. Chung Naomi H. Philip Valentina A. Schmidt Antonius Koller Till Strowig Richard A. Flavell Igor E. Brodsky James B. Bliska IQGAP1 Is Important for Activation of Caspase-1 in Macrophages and Is Targeted by <named-content content-type="genus-species">Yersinia pestis</named-content> Type III Effector YopM
description	ABSTRACT YopM is a leucine-rich repeat (LRR)-containing effector in several Yersinia species, including Yersinia pestis and Y. pseudotuberculosis. Different Yersinia strains encode distinct YopM isoforms with variable numbers of LRRs but conserved C-terminal tails. A 15-LRR isoform in Y. pseudotuberculosis YPIII was recently shown to bind and inhibit caspase-1 via a YLTD motif in LRR 10, and attenuation of YopM− YPIII was reversed in mice lacking caspase-1, indicating that caspase-1 inhibition is a major virulence function of YopMYPIII. To determine if other YopM proteins inhibit caspase-1, we utilized Y. pseudotuberculosis strains natively expressing a 21-LRR isoform lacking the YLTD motif (YopM32777) or ectopically expressing a Y. pestis 15-LRR version with a functional (YopMKIM) or inactivated (YopMKIM D271A) YLTD motif. Results of mouse and macrophage infections with these strains showed that YopM32777, YopMKIM, and YopMKIM D271A inhibit caspase-1 activation, indicating that the YLTD motif is dispensable for this activity. Analysis of YopMKIM deletion variants revealed that LRRs 6 to 15 and the C-terminal tail are required to inhibit caspase-1 activation. YopM32777, YopMKIM, and YopMKIM deletion variants were purified, and binding partners in macrophage lysates were identified. Caspase-1 bound to YopMKIM but not YopM32777. Additionally, YopMKIM bound IQGAP1 and the use of Iqgap1−/− macrophages revealed that this scaffolding protein is important for caspase-1 activation upon infection with YopM− Y. pseudotuberculosis. Thus, while multiple YopM isoforms inhibit caspase-1 activation, their variable LRR domains bind different host proteins to perform this function and the LRRs of YopMKIM target IQGAP1, a novel regulator of caspase-1, in macrophages. IMPORTANCE Activation of caspase-1, mediated by macromolecular complexes termed inflammasomes, is important for innate immune defense against pathogens. Pathogens can, in turn, subvert caspase-1-dependent responses through the action of effector proteins. For example, the Yersinia effector YopM inhibits caspase-1 activation by arresting inflammasome formation. This caspase-1 inhibitory activity has been studied in a specific YopM isoform, and in this case, the protein was shown to act as a pseudosubstrate to bind and inhibit caspase-1. Different Yersinia strains encode distinct YopM isoforms, many of which lack the pseudosubstrate motif. We studied additional isoforms and found that these YopM proteins inhibit caspase-1 activation independently of a pseudosubstrate motif. We also identified IQGAP1 as a novel binding partner of the Yersinia pestis YopMKIM isoform and demonstrated that IQGAP1 is important for caspase-1 activation in macrophages infected with Yersinia. Thus, this study reveals new insights into inflammasome regulation during Yersinia infection.
format	article
author	Lawton K. Chung Naomi H. Philip Valentina A. Schmidt Antonius Koller Till Strowig Richard A. Flavell Igor E. Brodsky James B. Bliska
author_facet	Lawton K. Chung Naomi H. Philip Valentina A. Schmidt Antonius Koller Till Strowig Richard A. Flavell Igor E. Brodsky James B. Bliska
author_sort	Lawton K. Chung
title	IQGAP1 Is Important for Activation of Caspase-1 in Macrophages and Is Targeted by <named-content content-type="genus-species">Yersinia pestis</named-content> Type III Effector YopM
title_short	IQGAP1 Is Important for Activation of Caspase-1 in Macrophages and Is Targeted by <named-content content-type="genus-species">Yersinia pestis</named-content> Type III Effector YopM
title_full	IQGAP1 Is Important for Activation of Caspase-1 in Macrophages and Is Targeted by <named-content content-type="genus-species">Yersinia pestis</named-content> Type III Effector YopM
title_fullStr	IQGAP1 Is Important for Activation of Caspase-1 in Macrophages and Is Targeted by <named-content content-type="genus-species">Yersinia pestis</named-content> Type III Effector YopM
title_full_unstemmed	IQGAP1 Is Important for Activation of Caspase-1 in Macrophages and Is Targeted by <named-content content-type="genus-species">Yersinia pestis</named-content> Type III Effector YopM
title_sort	iqgap1 is important for activation of caspase-1 in macrophages and is targeted by <named-content content-type="genus-species">yersinia pestis</named-content> type iii effector yopm
publisher	American Society for Microbiology
publishDate	2014
url	https://doaj.org/article/b52107ccd381415e9be79f32f4afdd51
work_keys_str_mv	AT lawtonkchung iqgap1isimportantforactivationofcaspase1inmacrophagesandistargetedbynamedcontentcontenttypegenusspeciesyersiniapestisnamedcontenttypeiiieffectoryopm AT naomihphilip iqgap1isimportantforactivationofcaspase1inmacrophagesandistargetedbynamedcontentcontenttypegenusspeciesyersiniapestisnamedcontenttypeiiieffectoryopm AT valentinaaschmidt iqgap1isimportantforactivationofcaspase1inmacrophagesandistargetedbynamedcontentcontenttypegenusspeciesyersiniapestisnamedcontenttypeiiieffectoryopm AT antoniuskoller iqgap1isimportantforactivationofcaspase1inmacrophagesandistargetedbynamedcontentcontenttypegenusspeciesyersiniapestisnamedcontenttypeiiieffectoryopm AT tillstrowig iqgap1isimportantforactivationofcaspase1inmacrophagesandistargetedbynamedcontentcontenttypegenusspeciesyersiniapestisnamedcontenttypeiiieffectoryopm AT richardaflavell iqgap1isimportantforactivationofcaspase1inmacrophagesandistargetedbynamedcontentcontenttypegenusspeciesyersiniapestisnamedcontenttypeiiieffectoryopm AT igorebrodsky iqgap1isimportantforactivationofcaspase1inmacrophagesandistargetedbynamedcontentcontenttypegenusspeciesyersiniapestisnamedcontenttypeiiieffectoryopm AT jamesbbliska iqgap1isimportantforactivationofcaspase1inmacrophagesandistargetedbynamedcontentcontenttypegenusspeciesyersiniapestisnamedcontenttypeiiieffectoryopm
_version_	1718427541686976512

IQGAP1 Is Important for Activation of Caspase-1 in Macrophages and Is Targeted by <named-content content-type="genus-species">Yersinia pestis</named-content> Type III Effector YopM

Ejemplares similares