Muscarinic acetylcholine receptors(mAChRs)play crucial roles in various physiological functions and pathophysiological processes.Acetylcholine(ACh),as a classical ligand and one of the pivotal neurotransmitters,serves as a prototype for the elucidation of molecular interaction and the development of mimicked and antagonized agents.With the advances in medicinal chemistry and structural biology,more and more mAChRs modulators derived from natural toxins have been identified.Based on the chemical structures and the receptor-ligand interaction modes,these mAChRs modulators can be divided into orthosteric modulators,allosteric modulators and other modulators.Moreover,allosteric modulators can be further divided into three groups:alcuronium-like modulators,staurosporine-like modulators,and phlegmarine-like modulators.In this review,we focus on various mAChRs modulators derived from natural toxins on the basis of the receptor-ligand interaction modes.The understanding of the affinity,the intrinsic efficacy,and the selectivity of mAChRs modulators may lead to the discovery of new drug leads for the treatment of diseases related to mAChRs.
Stat5是信号转导和转录活化蛋白(signal transduction and activator of transcription,Stat)家族的重要成员,它有两个序列高度同源的亚型Stat5a和Stat5b。与其他成员相比,Stat5参与了更为广泛的细胞生理调控过程。Stat5能够影响细胞的增殖、分化、存活与凋亡,并且在乳腺发育、免疫应答、干细胞自我更新调控、造血作用以及肿瘤的发生发展等中具有重要作用。本文综述了Stat5的信号转导机制及其生物学功能的研究,并探讨了今后在这一领域可能的发展方向。
Diverse subtypes of voltage-gated sodium channels(VGSCs)have been found throughout tissues of the brain,muscles and the heart.Neurotoxins extracted from the venom of the Asian scorpion Buthus martensi Karsch(BmK)act as sodium channel-specific modulators and have therefore been widely used to study VGSCs.α-type neurotoxins,named BmK I,BmKαIV and BmK abT,bind to receptor site-3 on VGSCs and can strongly prolong the inactivation phase of VGSCs.In contrast,β-type neurotoxins,named BmK AS,BmK AS-1,BmK IT and BmK IT2,occupy receptor site-4 on VGSCs and can suppress peak currents and hyperpolarize the activation kinetics of sodium channels.Accumulating evidence from binding assays of scorpion neurotoxins on VGSCs,however,indicate that pharmacological sensitivity of VGSC subtypes to different modulators is much more complex than that suggested by the simpleα-type and β-type neurotoxin distinction.Exploring the mechanisms of possible dynamic interactions between site 3-/4-specific modulators and region-and/or speciesspecific subtypes of VGSCs would therefore greatly expand our understanding of the physiological and pharmacological properties of diverse VGSCs.In this review,we discuss the pharmacological and structural diversity of VGSCs as revealed by studies exploring the binding properties and cross-competitive binding of site 3-or site 4-specific modulators in VGSC subtypes in synaptosomes from distinct tissues of diverse species.
