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Leishmania-induced IRAK-1 inactivation is mediated by SHP-1 interacting with an evolutionarily conserved KTIM motif.

Abu-Dayyeh I, Shio MT, Sato S, Akira S, Cousineau B, Olivier M - PLoS Negl Trop Dis (2008)

Bottom Line: We also demonstrate that the SHP-1/IRAK-1 interaction occurs via an evolutionarily conserved ITIM-like motif found in the kinase domain of IRAK-1, which we named KTIM (Kinase Tyrosyl-based Inhibitory Motif).This regulatory motif appeared in early vertebrates and is not found in any other IRAK family member.We thus provide the first demonstration that a pathogen can exploit a host protein tyrosine phosphatase, namely SHP-1, to directly inactivate IRAK-1 through a generally conserved KTIM motif.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada.

ABSTRACT
Parasites of the Leishmania genus can rapidly alter several macrophage (MØ) signalling pathways in order to tame down the innate immune response and inflammation, therefore favouring their survival and propagation within their mammalian host. Having recently reported that Leishmania and bacterial LPS generate a significantly stronger inflammatory response in animals and phagocytes functionally deficient for the Src homology 2 domain-containing protein tyrosine phosphatase (SHP-1), we hypothesized that Leishmania could exploit SHP-1 to inactivate key kinases involved in Toll-like receptor (TLR) signalling and innate immunity such as IL-1 receptor-associated kinase 1 (IRAK-1). Here we show that upon infection, SHP-1 rapidly binds to IRAK-1, completely inactivating its intrinsic kinase activity and any further LPS-mediated activation as well as MØ functions. We also demonstrate that the SHP-1/IRAK-1 interaction occurs via an evolutionarily conserved ITIM-like motif found in the kinase domain of IRAK-1, which we named KTIM (Kinase Tyrosyl-based Inhibitory Motif). This regulatory motif appeared in early vertebrates and is not found in any other IRAK family member. Our study additionally reveals that several other kinases (e.g. Erk1/2, IKKalpha/beta) involved in downstream TLR signalling also bear KTIMs in their kinase domains and interact with SHP-1. We thus provide the first demonstration that a pathogen can exploit a host protein tyrosine phosphatase, namely SHP-1, to directly inactivate IRAK-1 through a generally conserved KTIM motif.

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Related in: MedlinePlus

Inhibition of LPS-induced IRAK-1 kinase activity by Leishmania.(A) Kinase assay performed on IRAK-1 IPs from lysates of MØs uninfected and infected with L. donovani over a 6 h time-period. LPS stimulation (100 ng/ml, 30 min), positive control. (B) IRAK-1 kinase activity detected in IPs from lysates of MØs infected or not with pathogenic Leishmania species (L. donovani, L. mexicana, L. major) (20∶1 parasite to cell ratio, 1 h). Non-pathogenic lizard L. tarentolae was used as negative control. (C) Kinase assay of IRAK-1 IPs from lysates of naïve and L. donovani-infected MØs (O/N infection) subjected or not to LPS stimulation (100 ng/ml, 30 min). (D) IRAK-1 kinase activity in IPs from naïve and L. donovani-infected MØs (O/N infection) stimulated or not with various TLR ligands (MALP (100 ng/ml), LPS (100 ng/ml), flagellin (100 ng/ml), CpG (5 µg/ml); 30 min). All results are representative of at least three independent experiments.
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pntd-0000305-g006: Inhibition of LPS-induced IRAK-1 kinase activity by Leishmania.(A) Kinase assay performed on IRAK-1 IPs from lysates of MØs uninfected and infected with L. donovani over a 6 h time-period. LPS stimulation (100 ng/ml, 30 min), positive control. (B) IRAK-1 kinase activity detected in IPs from lysates of MØs infected or not with pathogenic Leishmania species (L. donovani, L. mexicana, L. major) (20∶1 parasite to cell ratio, 1 h). Non-pathogenic lizard L. tarentolae was used as negative control. (C) Kinase assay of IRAK-1 IPs from lysates of naïve and L. donovani-infected MØs (O/N infection) subjected or not to LPS stimulation (100 ng/ml, 30 min). (D) IRAK-1 kinase activity in IPs from naïve and L. donovani-infected MØs (O/N infection) stimulated or not with various TLR ligands (MALP (100 ng/ml), LPS (100 ng/ml), flagellin (100 ng/ml), CpG (5 µg/ml); 30 min). All results are representative of at least three independent experiments.

Mentions: As Leishmania activates host SHP-1 and blocks many LPS-mediated functions known to be detrimental to the parasite, we investigated the possibility that Leishmania inactivates IRAK-1. Kinase assays comparing IRAK-1 activity in MØs infected with L. donovani to uninfected cells revealed that the parasite caused a rapid time-dependent inactivation of IRAK-1 seen by reduced basal IRAK-1 activity in infected MØs (Figure 6A). To investigate whether IRAK-1 inactivation is a common mechanism utilized by other infectious Leishmania species, MØs were infected for 1 h with various Leishmania species promastigotes and IRAK-1 kinase activity was measured. L. donovani decreased IRAK-1 activity by 65±11% SD, and consistent with our expectation, L. mexicana and L. major were also able to inactivate IRAK-1 as they decreased IRAK-1 kinase activity by 65±7% SD and 52±4% SD, respectively (Figure 6B). Interestingly, L. tarentolae, a lizard non-pathogenic Leishmania did not inhibit IRAK-1 and seemed to even slightly activate it (increase of 20±11% SD).


Leishmania-induced IRAK-1 inactivation is mediated by SHP-1 interacting with an evolutionarily conserved KTIM motif.

Abu-Dayyeh I, Shio MT, Sato S, Akira S, Cousineau B, Olivier M - PLoS Negl Trop Dis (2008)

Inhibition of LPS-induced IRAK-1 kinase activity by Leishmania.(A) Kinase assay performed on IRAK-1 IPs from lysates of MØs uninfected and infected with L. donovani over a 6 h time-period. LPS stimulation (100 ng/ml, 30 min), positive control. (B) IRAK-1 kinase activity detected in IPs from lysates of MØs infected or not with pathogenic Leishmania species (L. donovani, L. mexicana, L. major) (20∶1 parasite to cell ratio, 1 h). Non-pathogenic lizard L. tarentolae was used as negative control. (C) Kinase assay of IRAK-1 IPs from lysates of naïve and L. donovani-infected MØs (O/N infection) subjected or not to LPS stimulation (100 ng/ml, 30 min). (D) IRAK-1 kinase activity in IPs from naïve and L. donovani-infected MØs (O/N infection) stimulated or not with various TLR ligands (MALP (100 ng/ml), LPS (100 ng/ml), flagellin (100 ng/ml), CpG (5 µg/ml); 30 min). All results are representative of at least three independent experiments.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2596967&req=5

pntd-0000305-g006: Inhibition of LPS-induced IRAK-1 kinase activity by Leishmania.(A) Kinase assay performed on IRAK-1 IPs from lysates of MØs uninfected and infected with L. donovani over a 6 h time-period. LPS stimulation (100 ng/ml, 30 min), positive control. (B) IRAK-1 kinase activity detected in IPs from lysates of MØs infected or not with pathogenic Leishmania species (L. donovani, L. mexicana, L. major) (20∶1 parasite to cell ratio, 1 h). Non-pathogenic lizard L. tarentolae was used as negative control. (C) Kinase assay of IRAK-1 IPs from lysates of naïve and L. donovani-infected MØs (O/N infection) subjected or not to LPS stimulation (100 ng/ml, 30 min). (D) IRAK-1 kinase activity in IPs from naïve and L. donovani-infected MØs (O/N infection) stimulated or not with various TLR ligands (MALP (100 ng/ml), LPS (100 ng/ml), flagellin (100 ng/ml), CpG (5 µg/ml); 30 min). All results are representative of at least three independent experiments.
Mentions: As Leishmania activates host SHP-1 and blocks many LPS-mediated functions known to be detrimental to the parasite, we investigated the possibility that Leishmania inactivates IRAK-1. Kinase assays comparing IRAK-1 activity in MØs infected with L. donovani to uninfected cells revealed that the parasite caused a rapid time-dependent inactivation of IRAK-1 seen by reduced basal IRAK-1 activity in infected MØs (Figure 6A). To investigate whether IRAK-1 inactivation is a common mechanism utilized by other infectious Leishmania species, MØs were infected for 1 h with various Leishmania species promastigotes and IRAK-1 kinase activity was measured. L. donovani decreased IRAK-1 activity by 65±11% SD, and consistent with our expectation, L. mexicana and L. major were also able to inactivate IRAK-1 as they decreased IRAK-1 kinase activity by 65±7% SD and 52±4% SD, respectively (Figure 6B). Interestingly, L. tarentolae, a lizard non-pathogenic Leishmania did not inhibit IRAK-1 and seemed to even slightly activate it (increase of 20±11% SD).

Bottom Line: We also demonstrate that the SHP-1/IRAK-1 interaction occurs via an evolutionarily conserved ITIM-like motif found in the kinase domain of IRAK-1, which we named KTIM (Kinase Tyrosyl-based Inhibitory Motif).This regulatory motif appeared in early vertebrates and is not found in any other IRAK family member.We thus provide the first demonstration that a pathogen can exploit a host protein tyrosine phosphatase, namely SHP-1, to directly inactivate IRAK-1 through a generally conserved KTIM motif.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada.

ABSTRACT
Parasites of the Leishmania genus can rapidly alter several macrophage (MØ) signalling pathways in order to tame down the innate immune response and inflammation, therefore favouring their survival and propagation within their mammalian host. Having recently reported that Leishmania and bacterial LPS generate a significantly stronger inflammatory response in animals and phagocytes functionally deficient for the Src homology 2 domain-containing protein tyrosine phosphatase (SHP-1), we hypothesized that Leishmania could exploit SHP-1 to inactivate key kinases involved in Toll-like receptor (TLR) signalling and innate immunity such as IL-1 receptor-associated kinase 1 (IRAK-1). Here we show that upon infection, SHP-1 rapidly binds to IRAK-1, completely inactivating its intrinsic kinase activity and any further LPS-mediated activation as well as MØ functions. We also demonstrate that the SHP-1/IRAK-1 interaction occurs via an evolutionarily conserved ITIM-like motif found in the kinase domain of IRAK-1, which we named KTIM (Kinase Tyrosyl-based Inhibitory Motif). This regulatory motif appeared in early vertebrates and is not found in any other IRAK family member. Our study additionally reveals that several other kinases (e.g. Erk1/2, IKKalpha/beta) involved in downstream TLR signalling also bear KTIMs in their kinase domains and interact with SHP-1. We thus provide the first demonstration that a pathogen can exploit a host protein tyrosine phosphatase, namely SHP-1, to directly inactivate IRAK-1 through a generally conserved KTIM motif.

Show MeSH
Related in: MedlinePlus