PT - JOURNAL ARTICLE AU - Craig Ulrich AU - David R. Quillici AU - Kathleen Schegg AU - Rebekah Woolsey AU - Akira Nordmeier AU - Iain L. O. Buxton TI - Uterine Smooth Muscle <em>S</em>-Nitrosylproteome in Pregnancy AID - 10.1124/mol.111.075804 DP - 2012 Feb 01 TA - Molecular Pharmacology PG - 143--153 VI - 81 IP - 2 4099 - http://molpharm.aspetjournals.org/content/81/2/143.short 4100 - http://molpharm.aspetjournals.org/content/81/2/143.full SO - Mol Pharmacol2012 Feb 01; 81 AB - 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 &lt; 0.005) in pregnancy and that this increase cannot be attributed solely to the increase in protein expression (1.8-fold, p &lt; 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.