mechanisms driving heme insertion into apo-sgc during its maturation in cells

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ORAL PRESENTATION Open Access Mechanisms driving heme insertion into apo-sGC during its maturation in cells Dennis Stuehr * , Arnab Ghosh, Anindya Sarkar, Yue Dai From 6th International Conference on cGMP: Generators, Effectors and Therapeutic Implications Erfurt, Germany. 28-30 June 2013 Background During maturation of soluble guanylyl cyclase (sGC), heme insertion into the beta subunit is essential because it enables sGC to recognize nitric oxide (NO) and transduce its biological effects. We used a mammalian cell culture approach and followed heme insertion into both transi- ently- and endogenously-expressed apo-sGC beta. Although sGC is often associated with heat shock protein 90 (hsp90) in cells, the implications are unclear. Experi- ments that used pharmacological hsp90 inhibitors, an ATP-ase inactive hsp90 mutant, and heme-dependent or heme-independent sGC activators revealed that heme insertion into apo-sGC requires hsp90 [1]. Results Our findings suggest a model where apo-sGC beta may directly complex with hsp90, which then drives heme insertion into apo-sGC beta through its inherent ATPase activity. In follow-up studies we are using purified proteins and domains and fluorescence and hydrogen-deuterium exchange methods to characterize the apo-sGC interaction with hsp90 at the molecular level. Results indicate that apo-sGC beta binds to the hsp90 middle domain, and the binding interaction involves structural regions within the heme and PAS domains of sGC. Conclusion Together, our work is shedding light on the sGC matura- tion process, and is revealing new ways that sGC activity could be impacted or controlled in cells. Published: 29 August 2013 Reference 1. Ghosh A, Stuehr DJ: Soluble guanylyl cyclase requires heat shock protein 90 for heme insertion during maturation of the NO-active enzyme. Proc Natl Acad Sci U S A 2012, 109:12998-13003. doi:10.1186/2050-6511-14-S1-O18 Cite this article as: Stuehr et al.: Mechanisms driving heme insertion into apo-sGC during its maturation in cells. BMC Pharmacology and Toxicology 2013 14(Suppl 1):O18. Submit your next manuscript to BioMed Central and take full advantage of: Convenient online submission Thorough peer review No space constraints or color figure charges Immediate publication on acceptance Inclusion in PubMed, CAS, Scopus and Google Scholar Research which is freely available for redistribution Submit your manuscript at www.biomedcentral.com/submit * Correspondence: [email protected] Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland Ohio, USA Stuehr et al. BMC Pharmacology and Toxicology 2013, 14(Suppl 1):O18 http://www.biomedcentral.com/2050-6511/14/S1/O18 © 2013 Stuehr et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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ORAL PRESENTATION Open Access

Mechanisms driving heme insertion into apo-sGCduring its maturation in cellsDennis Stuehr*, Arnab Ghosh, Anindya Sarkar, Yue Dai

From 6th International Conference on cGMP: Generators, Effectors and Therapeutic ImplicationsErfurt, Germany. 28-30 June 2013

BackgroundDuring maturation of soluble guanylyl cyclase (sGC),heme insertion into the beta subunit is essential because itenables sGC to recognize nitric oxide (NO) and transduceits biological effects. We used a mammalian cell cultureapproach and followed heme insertion into both transi-ently- and endogenously-expressed apo-sGC beta.Although sGC is often associated with heat shock protein90 (hsp90) in cells, the implications are unclear. Experi-ments that used pharmacological hsp90 inhibitors, anATP-ase inactive hsp90 mutant, and heme-dependent orheme-independent sGC activators revealed that hemeinsertion into apo-sGC requires hsp90 [1].

ResultsOur findings suggest a model where apo-sGC beta maydirectly complex with hsp90, which then drives hemeinsertion into apo-sGC beta through its inherent ATPaseactivity. In follow-up studies we are using purified proteinsand domains and fluorescence and hydrogen-deuteriumexchange methods to characterize the apo-sGC interactionwith hsp90 at the molecular level. Results indicate thatapo-sGC beta binds to the hsp90 middle domain, and thebinding interaction involves structural regions within theheme and PAS domains of sGC.

ConclusionTogether, our work is shedding light on the sGC matura-tion process, and is revealing new ways that sGC activitycould be impacted or controlled in cells.

Published: 29 August 2013

Reference1. Ghosh A, Stuehr DJ: Soluble guanylyl cyclase requires heat shock protein

90 for heme insertion during maturation of the NO-active enzyme. ProcNatl Acad Sci U S A 2012, 109:12998-13003.

doi:10.1186/2050-6511-14-S1-O18Cite this article as: Stuehr et al.: Mechanisms driving heme insertioninto apo-sGC during its maturation in cells. BMC Pharmacology andToxicology 2013 14(Suppl 1):O18.

Submit your next manuscript to BioMed Centraland take full advantage of:

• Convenient online submission

• Thorough peer review

• No space constraints or color figure charges

• Immediate publication on acceptance

• Inclusion in PubMed, CAS, Scopus and Google Scholar

• Research which is freely available for redistribution

Submit your manuscript at www.biomedcentral.com/submit

* Correspondence: [email protected] of Pathobiology, Lerner Research Institute, Cleveland Clinic,Cleveland Ohio, USA

Stuehr et al. BMC Pharmacology and Toxicology 2013, 14(Suppl 1):O18http://www.biomedcentral.com/2050-6511/14/S1/O18

© 2013 Stuehr et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative CommonsAttribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction inany medium, provided the original work is properly cited.