Na,K-ATPase alpha4 isoform in male germ cell physiology

男性生殖细胞生理学中的 Na,K-ATP 酶 α4 亚型

基本信息

批准号：
7920828
负责人：
V GUSTAVO BLANCO
金额：
$ 36.03万
依托单位：
UNIVERSITY OF KANSAS MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2003
资助国家：
美国
起止时间：
2003-08-01 至 2012-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7920828
关键词：
ATP Hydrolysis Acrosome Reaction Affinity Albumins Bicarbonates Binding Biochemical Biological Biology Cardenolides Cell membrane Cell physiology Cells Characteristics Contraceptive methods Cyclic AMP Data Development Event Exhibits Female Fertility Future Genital system Germ Cells Goals Growth Hormones In Vitro Ion Transport Ions Isoenzymes Laboratories Mediating Mediator of activation protein Meiosis Membrane Membrane Potentials Metabolism Molecular Na(+)-K(+)-Exchanging ATPase Ouabain Pathway interactions Pattern Phosphorylation Physiology Play Process Protein Isoforms Proteins Publishing Regulation Research Role Seminal fluid Series Signal Transduction Signaling Molecule Somatic Cell Sperm Capacitation Sperm Motility System Testing Up-Regulation Work base cell motility design expectation extracellular innovation male novel polypeptide research study sperm cell sperm function tool

项目摘要

The Na,K-ATPase transporters comprise a group of relatively ubiquitous plasma membrane isozymes that use the energy from the hydrolysis of ATP to exchange cytoplasmic Na+ for extracellular K+. Isozyme diversity for the Na,K-ATPase results from the association of different molecular forms, or isoforms of two polypeptides, the catalytic α and glycosylated β subunits. Among these isoforms, the α4 polypeptide has the most restricted pattern of expression, and is selectively present in male germ cells. The α4 isoform exhibits several biochemical and functional characteristics that are highly unique and essential to sperm function. Importantly, α4 is necessary for normal motility of spermatozoa. Supporting its biological importance, we have shown that α4 undergoes significant developmental changes, and that its level of expression and activity increase dramatically after sperm meiosis. Once released, spermatozoa continue to undergo critical maturational changes that are essential for the cells to acquire their fertilizing ability. During this process, called capacitation, we found α4 activity to be up-regulated. While these results suggest an important role for α4 in sperm function, the precise mechanism(s) by which this protein contributes to sperm capacitation to regulate sperm fertility has yet to be fully defined. Our overall goal in this research is to determine the mechanism(s) by which the activity and ion transport function of the α4 isoform is regulated and the relevance of this event in sperm capacitation. Our central hypothesis is that the α4 isoform plays an important role in sperm physiology to maintain the ion gradients that control pH, membrane potential and motility changes that are hallmarks of sperm capacitation. Experiments are designed to identify the factors and mechanisms responsible for up-regulation of α4 activity, and to determine the contribution of these events to sperm capacitation. The results will have an important positive impact, because they will help to define the molecular basis of sperm capacitation and will contribute to future pharmacologic approaches that will target the α4 isoform to control male fertility.

Na，K-ATPase转运蛋白包含一组相对普遍存在的质膜同工酶，这些质膜同工酶利用ATP水解的能量将细胞质Na+交换为细胞外K+。 Na，K-ATPase的同工酶多样性是由不同分子形式的缔合或两个多肽的同工型的关联，即催化α和糖基化的β亚基。在这些同工型中，α4多肽的表达模式最严格，并且在男性生殖细胞中有选择性地存在。 α4同工型表现出多种生化和功能特征，这些特性高度独特，对精子功能至关重要。重要的是，α4对于精子的正常运动是必需的。支持其生物学重要性，我们表明α4经历了重大的发育变化，并且其表达水平和活性水平在精子减数分裂后急剧增加。释放后，精子继续进行关键的成熟变化，这对于细胞获得其受精能力至关重要。在此过程中，我们发现α4活性被上调。尽管这些结果表明α4在精子功能中起着重要作用，但该蛋白有助于调节精子生育能力的精子能力的精确机制尚未得到充分定义。我们在这项研究中的总体目标是确定调节α4同工型的活性和离子传输功能以及该事件在精子电容中的相关性的机制。我们的中心假设是，α4同工型在精子生理学中起着重要作用，以维持控制pH值，膜电位和运动性变化的离子梯度，这些变化是精子电容的标志。实验旨在确定负责上调α4活性的因素和机制，并确定这些因素的贡献精子电容的事件。结果将产生重要的积极影响，因为它们将有助于定义精子电容的分子基础，并有助于未来的药理学方法，该方法将以α4同工型来控制男性生育能力。