Abstract
The molecular mechanisms involved in uterine quiescence during gestation and those responsible for induction of labor are not completely known. Nitric oxide relaxes uterine smooth muscle in a manner disparate from that for other smooth muscles because global elevation of cGMP after activation of soluble guanylyl cyclase does not relax the muscle. S-Nitrosylation, the covalent addition of an nitric oxide (NO) group to a cysteine thiol is a likely mechanism to explain the ability of NO to relax myometrium. This work is the first to describe the myometrial S-nitrosylproteome in both pregnant and nonpregnant tissue states. Using the guinea pig model, we show that specific sets of proteins involved in contraction and relaxation are S-nitrosylated in laboring and nonlaboring muscle and that many of these proteins are uniquely S-nitrosylated in only one state of the tissue. In particular, we show that S-nitrosylation of the intermediate filament protein desmin is significantly increased (5.7-fold, p < 0.005) in pregnancy and that this increase cannot be attributed solely to the increase in protein expression (1.8-fold, p < 0.005) that accompanies pregnancy. Elucidation of the myometrial S-nitrosylproteome provides a list of mechanistically important proteins that can constitute the basis of hypotheses formed to explain the regulation of uterine contraction/relaxation.
Footnotes
This work was supported by the National Institutes of Health Eunice Kennedy Shriver National Institute of Child Health and Human Development [Grant R01-HD053028]; National Institutes of Health National Center for Research Resources [Grant P20-RR016464]; and a Gates Grand Challenges Grant (to I.L.O.B.).
Article, publication date, and citation information can be found at http://molpharm.aspetjournals.org.
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ABBREVIATIONS:
- USM
- uterine smooth muscle
- NO
- nitric oxide
- LY 83583
- 6-anilino-5,8-quinolinedione
- NEM
- N-ethylmaleimide
- CHAPS
- 3-(3-cholamidopropyl)dimethylammonio-1-propanesulfonate
- biotin-HPDP
- N-[6-(biotinamido)hexyl]-3′-(2′-pyridyldithio) propionamide
- GSNO
- S-nitroso-glutathione
- LC
- liquid chromatography
- MS/MS
- tandem mass spectrometry
- DIGE
- two-dimensional in-gel electrophoresis
- MS
- mass spectrometry
- MALDI
- matrix-assisted laser desorption ionization
- TOF/TOF
- tandem time of flight
- S/N
- signal/noise ratio
- SNO
- S-nitrosothiol
- MYLK
- myosin light chain kinase
- HSP27
- heat shock protein β-1
- IF
- intermediate filament.
- Received September 16, 2011.
- Accepted October 25, 2011.
- Copyright © 2012 The American Society for Pharmacology and Experimental Therapeutics
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