Factors Required for Activation of Urease as a Virulence Determinant in <named-content content-type="genus-species">Cryptococcus neoformans</named-content>

ABSTRACT Urease in Cryptococcus neoformans plays an important role in fungal dissemination to the brain and causing meningoencephalitis. Although urea is not required for synthesis of apourease encoded by URE1, the available nitrogen source affected the expression of URE1 as well as the level of the...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Arpita Singh, Robert J. Panting, Ashok Varma, Tomomi Saijo, Kevin J. Waldron, Ambrose Jong, Popchai Ngamskulrungroj, Yun C. Chang, Julian C. Rutherford, Kyung J. Kwon-Chung
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2013
Materias:	Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/e1799b6ddd5e457a8165e02ca311d6d4
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:e1799b6ddd5e457a8165e02ca311d6d4
record_format	dspace
spelling	oai:doaj.org-article:e1799b6ddd5e457a8165e02ca311d6d42021-11-15T15:40:05ZFactors Required for Activation of Urease as a Virulence Determinant in <named-content content-type="genus-species">Cryptococcus neoformans</named-content>10.1128/mBio.00220-132150-7511https://doaj.org/article/e1799b6ddd5e457a8165e02ca311d6d42013-07-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.00220-13https://doaj.org/toc/2150-7511ABSTRACT Urease in Cryptococcus neoformans plays an important role in fungal dissemination to the brain and causing meningoencephalitis. Although urea is not required for synthesis of apourease encoded by URE1, the available nitrogen source affected the expression of URE1 as well as the level of the enzyme activity. Activation of the apoenzyme requires three accessory proteins, Ure4, Ure6, and Ure7, which are homologs of the bacterial urease accessory proteins UreD, UreF, and UreG, respectively. A yeast two-hybrid assay showed positive interaction of Ure1 with the three accessory proteins encoded by URE4, URE6, and URE7. Metalloproteomic analysis of cryptococcal lysates using inductively coupled plasma mass spectrometry (ICP-MS) and a biochemical assay of urease activity showed that, as in many other organisms, urease is a metallocentric enzyme that requires nickel transported by Nic1 for its catalytic activity. The Ure7 accessory protein (bacterial UreG homolog) binds nickel likely via its conserved histidine-rich domain and appears to be responsible for the incorporation of Ni2+ into the apourease. Although the cryptococcal genome lacks the bacterial UreE homolog, Ure7 appears to combine the functions of bacterial UreE and UreG, thus making this pathogen more similar to that seen with the plant system. Brain invasion by the ure1, ure7, and nic1 mutant strains that lack urease activity was significantly less effective in a mouse model. This indicated that an activated urease and not the Ure1 protein was responsible for enhancement of brain invasion and that the factors required for urease activation in C. neoformans resemble those of plants more than those of bacteria. IMPORTANCE Cryptococcus neoformans is the major fungal agent of meningoencephalitis in humans. Although urease is an important factor for cryptococcal brain invasion, the enzyme activation system has not been studied. We show that urease is a nickel-requiring enzyme whose activity level is influenced by the type of available nitrogen source. C. neoformans contains all the bacterial urease accessory protein homologs and nickel transporters except UreE, a nickel chaperone. Cryptococcal Ure7 (a homolog of UreG) apparently functions as both the bacterial UreG and UreE in activating the Ure1 apoenzyme. The cryptococcal urease accessory proteins Ure4, Ure6, and Ure7 interacted with Ure1 in a yeast two-hybrid assay, and deletion of any one of these not only inactivated the enzyme but also reduced the efficacy of brain invasion. This is the first study showing a holistic picture of urease in fungi, clarifying that urease activity, and not Ure1 protein, contributes to pathogenesis in C. neoformansArpita SinghRobert J. PantingAshok VarmaTomomi SaijoKevin J. WaldronAmbrose JongPopchai NgamskulrungrojYun C. ChangJulian C. RutherfordKyung J. Kwon-ChungAmerican Society for MicrobiologyarticleMicrobiologyQR1-502ENmBio, Vol 4, Iss 3 (2013)
institution	DOAJ
collection	DOAJ
language	EN
topic	Microbiology QR1-502
spellingShingle	Microbiology QR1-502 Arpita Singh Robert J. Panting Ashok Varma Tomomi Saijo Kevin J. Waldron Ambrose Jong Popchai Ngamskulrungroj Yun C. Chang Julian C. Rutherford Kyung J. Kwon-Chung Factors Required for Activation of Urease as a Virulence Determinant in <named-content content-type="genus-species">Cryptococcus neoformans</named-content>
description	ABSTRACT Urease in Cryptococcus neoformans plays an important role in fungal dissemination to the brain and causing meningoencephalitis. Although urea is not required for synthesis of apourease encoded by URE1, the available nitrogen source affected the expression of URE1 as well as the level of the enzyme activity. Activation of the apoenzyme requires three accessory proteins, Ure4, Ure6, and Ure7, which are homologs of the bacterial urease accessory proteins UreD, UreF, and UreG, respectively. A yeast two-hybrid assay showed positive interaction of Ure1 with the three accessory proteins encoded by URE4, URE6, and URE7. Metalloproteomic analysis of cryptococcal lysates using inductively coupled plasma mass spectrometry (ICP-MS) and a biochemical assay of urease activity showed that, as in many other organisms, urease is a metallocentric enzyme that requires nickel transported by Nic1 for its catalytic activity. The Ure7 accessory protein (bacterial UreG homolog) binds nickel likely via its conserved histidine-rich domain and appears to be responsible for the incorporation of Ni2+ into the apourease. Although the cryptococcal genome lacks the bacterial UreE homolog, Ure7 appears to combine the functions of bacterial UreE and UreG, thus making this pathogen more similar to that seen with the plant system. Brain invasion by the ure1, ure7, and nic1 mutant strains that lack urease activity was significantly less effective in a mouse model. This indicated that an activated urease and not the Ure1 protein was responsible for enhancement of brain invasion and that the factors required for urease activation in C. neoformans resemble those of plants more than those of bacteria. IMPORTANCE Cryptococcus neoformans is the major fungal agent of meningoencephalitis in humans. Although urease is an important factor for cryptococcal brain invasion, the enzyme activation system has not been studied. We show that urease is a nickel-requiring enzyme whose activity level is influenced by the type of available nitrogen source. C. neoformans contains all the bacterial urease accessory protein homologs and nickel transporters except UreE, a nickel chaperone. Cryptococcal Ure7 (a homolog of UreG) apparently functions as both the bacterial UreG and UreE in activating the Ure1 apoenzyme. The cryptococcal urease accessory proteins Ure4, Ure6, and Ure7 interacted with Ure1 in a yeast two-hybrid assay, and deletion of any one of these not only inactivated the enzyme but also reduced the efficacy of brain invasion. This is the first study showing a holistic picture of urease in fungi, clarifying that urease activity, and not Ure1 protein, contributes to pathogenesis in C. neoformans
format	article
author	Arpita Singh Robert J. Panting Ashok Varma Tomomi Saijo Kevin J. Waldron Ambrose Jong Popchai Ngamskulrungroj Yun C. Chang Julian C. Rutherford Kyung J. Kwon-Chung
author_facet	Arpita Singh Robert J. Panting Ashok Varma Tomomi Saijo Kevin J. Waldron Ambrose Jong Popchai Ngamskulrungroj Yun C. Chang Julian C. Rutherford Kyung J. Kwon-Chung
author_sort	Arpita Singh
title	Factors Required for Activation of Urease as a Virulence Determinant in <named-content content-type="genus-species">Cryptococcus neoformans</named-content>
title_short	Factors Required for Activation of Urease as a Virulence Determinant in <named-content content-type="genus-species">Cryptococcus neoformans</named-content>
title_full	Factors Required for Activation of Urease as a Virulence Determinant in <named-content content-type="genus-species">Cryptococcus neoformans</named-content>
title_fullStr	Factors Required for Activation of Urease as a Virulence Determinant in <named-content content-type="genus-species">Cryptococcus neoformans</named-content>
title_full_unstemmed	Factors Required for Activation of Urease as a Virulence Determinant in <named-content content-type="genus-species">Cryptococcus neoformans</named-content>
title_sort	factors required for activation of urease as a virulence determinant in <named-content content-type="genus-species">cryptococcus neoformans</named-content>
publisher	American Society for Microbiology
publishDate	2013
url	https://doaj.org/article/e1799b6ddd5e457a8165e02ca311d6d4
work_keys_str_mv	AT arpitasingh factorsrequiredforactivationofureaseasavirulencedeterminantinnamedcontentcontenttypegenusspeciescryptococcusneoformansnamedcontent AT robertjpanting factorsrequiredforactivationofureaseasavirulencedeterminantinnamedcontentcontenttypegenusspeciescryptococcusneoformansnamedcontent AT ashokvarma factorsrequiredforactivationofureaseasavirulencedeterminantinnamedcontentcontenttypegenusspeciescryptococcusneoformansnamedcontent AT tomomisaijo factorsrequiredforactivationofureaseasavirulencedeterminantinnamedcontentcontenttypegenusspeciescryptococcusneoformansnamedcontent AT kevinjwaldron factorsrequiredforactivationofureaseasavirulencedeterminantinnamedcontentcontenttypegenusspeciescryptococcusneoformansnamedcontent AT ambrosejong factorsrequiredforactivationofureaseasavirulencedeterminantinnamedcontentcontenttypegenusspeciescryptococcusneoformansnamedcontent AT popchaingamskulrungroj factorsrequiredforactivationofureaseasavirulencedeterminantinnamedcontentcontenttypegenusspeciescryptococcusneoformansnamedcontent AT yuncchang factorsrequiredforactivationofureaseasavirulencedeterminantinnamedcontentcontenttypegenusspeciescryptococcusneoformansnamedcontent AT juliancrutherford factorsrequiredforactivationofureaseasavirulencedeterminantinnamedcontentcontenttypegenusspeciescryptococcusneoformansnamedcontent AT kyungjkwonchung factorsrequiredforactivationofureaseasavirulencedeterminantinnamedcontentcontenttypegenusspeciescryptococcusneoformansnamedcontent
_version_	1718427799349362688

Factors Required for Activation of Urease as a Virulence Determinant in <named-content content-type="genus-species">Cryptococcus neoformans</named-content>

Ejemplares similares