KLC3 is involved in sperm tail midpiece formation and sperm function.
KLC3 is involved in sperm tail midpiece formation and sperm function.
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DOI：
10.1016/j.ydbio.2012.04.026
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发表时间：
2012-06
影响因子：
2.7
通讯作者：
Ying Zhang;Y. Ou;M. Cheng;Habib Saadi;J. Thundathil;F. A. van der Hoorn
中科院分区：
文献类型：
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作者：
Ying Zhang;Y. Ou;M. Cheng;Habib Saadi;J. Thundathil;F. A. van der Hoorn
运动蛋白轻链3(KLC3)是目前已知的唯一在减数分裂后的雄性生殖细胞中表达的运动蛋白轻链。我们已经报道，在大鼠精子细胞中，KLC3与外密纤维和线粒体鞘相关。KLC3在体外和体内都能通过轻链保守的四肽重复序列与线粒体结合。KLC3与线粒体的时间表达和结合与精子发生阶段相吻合，此时线粒体从精子细胞外围移动到发育中的中段，提示在中段的形成中发挥了作用。在成纤维细胞中，KLC3的表达导致在靠近含有线粒体的细胞核附近形成大的KLC3聚集体。然而，KLC3聚集线粒体的分子基础及其在精子尾部中段形成中的作用尚不清楚。在这里，我们表明，来自诱导系统的KLC3的表达在6小时内以微管依赖的方式引起线粒体聚集。我们鉴定了线粒体外膜孔蛋白VDAC2为KLC3结合伙伴。为了分析KLC3在精子细胞中的作用，我们建立了一个转基因小鼠模型，在该模型中，KLC3ΔHR突变蛋白在精子细胞中特异表达：这种KLC3突变蛋白结合线粒体并导致聚集形成，但不能结合外部致密纤维。雄性转基因小鼠在产下小鼠后表现出显著的繁殖效率下降。我们在一些转基因精子细胞中观察到线粒体鞘结构的缺陷。转基因男性的精子数量显著减少，并产生表现出异常运动参数的精子。我们的结果表明，KLC3在精子发生、精子中段的发育和精子的正常功能中起作用。
Kinesin light chain 3 (KLC3) is the only known kinesin light chain expressed in post-meiotic male germ cells. We have reported that in rat spermatids KLC3 associates with outer dense fibers and mitochondrial sheath. KLC3 is able to bind to mitochondria in vitro and in vivo employing the conserved tetratrico-peptide repeat kinesin light chain motif. The temporal expression and association of KLC3 with mitochondria coincides with the stage in spermatogenesis when mitochondria move from the spermatid cell periphery to the developing midpiece suggesting a role in midpiece formation. In fibroblasts, expression of KLC3 results in formation of large KLC3 aggregates close to the nucleus that contain mitochondria. However, the molecular basis of the aggregation of mitochondria by KLC3 and its role in sperm tail midpiece formation are not clear. Here we show that KLC3 expression from an inducible system causes mitochondrial aggregation within 6h in a microtubule dependent manner. We identified the mitochondrial outer membrane porin protein VDAC2 as a KLC3 binding partner. To analyze a role for KLC3 in spermatids we developed a transgenic mouse model in which a KLC3ΔHR mutant protein is specifically expressed in spermatids: this KLC3 mutant protein binds mitochondria and causes aggregate formation, but cannot bind outer dense fibers. Male transgenic mice display significantly reduced reproductive efficiency siring small sized litters. We observed defects in the mitochondrial sheath structure in a number of transgenic spermatids. Transgenic males have a significantly reduced sperm count and produce spermatozoa that exhibit abnormal motility parameters. Our results indicate that KLC3 plays a role during spermiogenesis in the development of the midpiece and in the normal function of spermatozoa.