Proteasomal control of cytokinin synthesis protects Mycobacterium tuberculosis against nitric oxide.
One of several roles of the Mycobacterium tuberculosis proteasome is to defend against host-produced nitric oxide (NO), a free radical that can damage numerous biological macromolecules. Mutations that inactivate proteasomal degradation in Mycobacterium tuberculosis result in bacteria that are hypersensitive to NO and attenuated for growth in vivo, but it was not known why. To elucidate the link between proteasome function, NO resistance, and pathogenesis, we screened for suppressors of NO hypersensitivity in a mycobacterial proteasome ATPase mutant and identified mutations in Rv1205. We determined that Rv1205 encodes a pupylated proteasome substrate. Rv1205 is a homolog of the plant enzyme LONELY GUY, which catalyzes the production of hormones called cytokinins. Remarkably, we report that an obligate human pathogen secretes several cytokinins. Finally, we determined that the Rv1205-dependent accumulation of cytokinin breakdown products is likely responsible for the sensitization of Mycobacterium tuberculosis proteasome-associated mutants to NO.
Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA.
Marie I
MI
Samanovic
Howard Hughes Medical Institute, Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA.
Shengjiang
S
Tu
Department of Metabolomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, 78371 Olomouc, Czech Republic; Laboratory of Growth Regulators, Institute of Experimental Botany AS CR, 78371 Olomouc, Czech Republic.
Ondřej
O
Novák
National Center for Biotechnology Information, National Library of Medicine, NIH, Bethesda, MD 20894, USA.
Lakshminarayan M
LM
Iyer
Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
Fiona E
FE
McAllister
National Center for Biotechnology Information, National Library of Medicine, NIH, Bethesda, MD 20894, USA.
L
L
Aravind
Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
Steven P
SP
Gygi
Department of Biochemistry and Molecular Pharmacology, The Skirball Institute, New York University School of Medicine, New York, NY 10016, USA.
Stevan R
SR
Hubbard
Department of Metabolomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, 78371 Olomouc, Czech Republic; Laboratory of Growth Regulators, Institute of Experimental Botany AS CR, 78371 Olomouc, Czech Republic.
Miroslav
M
Strnad
Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA. Electronic address: heran.darwin@med.nyu.edu.
K Heran
KH
Darwin
D000447:Aldehydes / Q000378:metabolism; D000619:Aminohydrolases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D029681:Arabidopsis Proteins / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D003583:Cytokinins / Q000096:biosynthesis* / Q000378:metabolism; D054884:Host-Pathogen Interactions; D008810:Mice, Inbred C57BL; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D009569:Nitric Oxide / Q000378:metabolism* / Q000494:pharmacology; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D013489:Suppression, Genetic
D000447:Aldehydes; D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D003583:Cytokinins; D009569:Nitric Oxide; D046988:Proteasome Endopeptidase Complex; D000619:Aminohydrolases; C000589428:cytokinin riboside 5'-monophosphate phosphoribohydrolase, Arabidopsis