ABSTRACT
cAMP signaling is a fundamental cellular process necessary for mediating responses to hormonal stimuli. In contrast to cAMP-dependent activation of protein kinase A (PKA), an important cellular target, far less is known on termination in cAMP signaling, specifically how phosphodiesterases (PDEs) facilitate dissociation and hydrolysis of bound cAMP. In this study, we have probed the dynamics of a ternary complex of PKA and a PDE-RegA with an excess of a PDE-nonhydrolyzable cAMP analog, Sp-cAMPS by amide hydrogen/deuterium exchange mass spectrometry (HDXMS). Our results highlight how HDXMS can be used to monitor reactions together with mapping conformational dynamics of transient signaling complexes. Our results confirm a two-state model for active RegA-mediated dissociation of bound cAMP. Further, our results reveal that Sp-cAMPS and RegA mediate mutually exclusive interactions with the same region of PKA and at specific concentrations of Sp-cAMPS, RegA is capable of blocking Sp-cAMPS reassociation to PKA. This provides a molecular basis for how PDEs modulate levels of intracellular cAMP so that PKA is better suited to responding to fluxes rather than constant levels of cAMP. This study underscores how HDXMS can be a powerful tool for monitoring reactions together with mapping conformational dynamics in signaling proteins. This article is part of a Special Issue entitled: Mass spectrometry in structural biology.
Subject(s)
Cyclic AMP-Dependent Protein Kinases/chemistry , Cyclic AMP/chemistry , Phosphoric Diester Hydrolases/chemistry , Ternary Complex Factors/chemistry , Amides/chemistry , Cyclic AMP/metabolism , Cyclic AMP-Dependent Protein Kinases/metabolism , Deuterium/chemistry , Deuterium Exchange Measurement/methods , Hydrogen/chemistry , Mass Spectrometry/methods , Molecular Dynamics Simulation , Phosphoric Diester Hydrolases/metabolism , Protein Conformation , Signal TransductionABSTRACT
Objective To investigate the relationship between the zinc and copper concentration and the clinical outcomes of in vitro fertilization and embryo transfer(ivf-et).Methods The clinical data and zinc and copper concentration of serum on the days with human Chorionic gonadotropin(hCG) injection as well as that in the follicular fluid on the the day of oocyte retrieval were retrospectively analyzed in 43 cases with IVF-ET cycles.Results Application of pearson correlation analysis showed that copper concentration in follicular fluid of the 43 cases was positively correlated with the numbers of retrieved oocytes,fertilized oocytes and cleaved embryos( r were 0.392,0.327 and 0.321,respectively,P were 0.0094,0.0325 and 0.0361 respectively ) Between the pregnant group and non-pregnant group,the zinc and copper concentration in follicular fluid was not significantly different ( P ＞ 0.05 ) ; the serum estradiol ( E2 ) on the day of hCG administration was of significantly different(t =2.177,P =0.0353 );the serum zinc concentration on the day of hCG administration was of significantly different ( t =2.153,P =0.0372).Conclusion Trace elements zinc and copper might play an important role in the process of IVF-ET.
ABSTRACT
Objective To analyze the clinical correlation between UU infection and tubal pregnancy in order to guide the correct clinical treatment. Methods Cultivation was used to detect UU in villi tissue of 30 tubal preg-nancy patients and natural aborted pregnant women respectively. Results There was remarkable difference(P0.05) between the positive rate of UU in tubal pregnancy(80 % ) and natural pregnancy(16.7 % ). Conclusion UU may be one of major pathogenic microorganisms in tubal pregnancy, and it's necessary to detect and treat UU con-ventionally.
