TY - JOUR
T1 - IP3-4 kinase Arg1 regulates cell wall homeostasis and surface architecture to promote clearance of Cryptococcus neoformans infection in a mouse model
AU - Li, Cecilia
AU - Lev, Sophie
AU - Desmarini, Desmarini
AU - Kaufman-Francis, Keren
AU - Saiardi, Adolfo
AU - Silva, Ana P.G.
AU - Mackay, Joel P.
AU - Thompson, Philip E.
AU - Sorrell, Tania C.
AU - Djordjevic, Julianne T.
N1 - Funding Information:
This work was supported by a National Health and Medical Research Council of Australia (NHMRC) project grant (APP1058779_Djordjevic). CL is supported by an Australian Postgraduate Award. SL is supported by a Westmead Institute for Medical Research (WIMR) Career Development award. AS is supported by the Medical Research Council (MRC) core support to the MRC/UCL Laboratory for Molecular Cell Biology University Unit (MC_UU_1201814). JPM is supported by a Senior Research Fellowship from the NHMRC. TCS is supported by the Sydney Medical School Foundation.
Publisher Copyright:
© 2017 Taylor & Francis.
PY - 2017/12/8
Y1 - 2017/12/8
N2 - We previously identified a series of inositol polyphosphate kinases (IPKs), Arg1, Ipk1, Kcs1 and Asp1, in the opportunistic fungal pathogen Cryptococcus neoformans. Using gene deletion analysis, we characterized Arg1, Ipk1 and Kcs1 and showed that they act sequentially to convert IP3 to PP-IP5 (IP7), a key metabolite promoting stress tolerance, metabolic adaptation and fungal dissemination to the brain. We have now directly characterized the enzymatic activity of Arg1, demonstrating that it is a dual specificity (IP3/IP4) kinase producing IP5. We showed previously that IP5 is further phosphorylated by Ipk1 to produce IP6, which is a substrate for the synthesis of PP-IP5 by Kcs1. Phenotypic comparison of the arg1Δ and kcs1Δ deletion mutants (both PP-IP5-deficient) reveals that arg1Δ has the most deleterious phenotype: while PP-IP5 is essential for metabolic and stress adaptation in both mutant strains, PP-IP5 is dispensable for virulence-associated functions such as capsule production, cell wall organization, and normal N-linked mannosylation of the virulence factor, phospholipase B1, as these phenotypes were defective only in arg1Δ. The more deleterious arg1Δ phenotype correlated with a higher rate of arg1Δ phagocytosis by human peripheral blood monocytes and rapid arg1Δ clearance from lung in a mouse model. This observation is in contrast to kcs1Δ, which we previously reported establishes a chronic, confined lung infection. In summary, we show that Arg1 is the most crucial IPK for cryptococcal virulence, conveying PP-IP5–dependent and novel PP-IP5–independent functions.
AB - We previously identified a series of inositol polyphosphate kinases (IPKs), Arg1, Ipk1, Kcs1 and Asp1, in the opportunistic fungal pathogen Cryptococcus neoformans. Using gene deletion analysis, we characterized Arg1, Ipk1 and Kcs1 and showed that they act sequentially to convert IP3 to PP-IP5 (IP7), a key metabolite promoting stress tolerance, metabolic adaptation and fungal dissemination to the brain. We have now directly characterized the enzymatic activity of Arg1, demonstrating that it is a dual specificity (IP3/IP4) kinase producing IP5. We showed previously that IP5 is further phosphorylated by Ipk1 to produce IP6, which is a substrate for the synthesis of PP-IP5 by Kcs1. Phenotypic comparison of the arg1Δ and kcs1Δ deletion mutants (both PP-IP5-deficient) reveals that arg1Δ has the most deleterious phenotype: while PP-IP5 is essential for metabolic and stress adaptation in both mutant strains, PP-IP5 is dispensable for virulence-associated functions such as capsule production, cell wall organization, and normal N-linked mannosylation of the virulence factor, phospholipase B1, as these phenotypes were defective only in arg1Δ. The more deleterious arg1Δ phenotype correlated with a higher rate of arg1Δ phagocytosis by human peripheral blood monocytes and rapid arg1Δ clearance from lung in a mouse model. This observation is in contrast to kcs1Δ, which we previously reported establishes a chronic, confined lung infection. In summary, we show that Arg1 is the most crucial IPK for cryptococcal virulence, conveying PP-IP5–dependent and novel PP-IP5–independent functions.
KW - cell wall
KW - Cryptococcus neoformans
KW - inositol polyphosphate kinase
KW - inositol pyrophosphate
KW - IP
KW - meningitis
KW - molecular fungal pathogenesis
KW - mouse model
KW - PP-IP
KW - virulence
UR - http://www.scopus.com/inward/record.url?scp=85040535275&partnerID=8YFLogxK
U2 - 10.1080/21505594.2017.1385692
DO - 10.1080/21505594.2017.1385692
M3 - Article
C2 - 28976803
AN - SCOPUS:85040535275
SN - 2150-5594
VL - 8
SP - 1833
EP - 1848
JO - Virulence
JF - Virulence
IS - 8
ER -