Monoclonal antibodies increase intracellular Ca2+ in sea urchin spermatozoa.
Monoclonal antibodies increase intracellular Ca2+ in sea urchin spermatozoa.
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单克隆抗体可增加海胆精子中的细胞内 Ca2+。
DOI：
10.1073/pnas.83.23.9055
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发表时间：
1986
影响因子：
11.1
通讯作者：
Vacquier,VD
中科院分区：
文献类型：
--
作者：
Trimmer,JS;Schackmann,RW;Vacquier,VD
采用荧光Ca2+指示剂fura-2和indo-1测定海胆（strongylocentrrotus purpuratus）精子胞内游离Ca2+ ([Ca2+]i)变化。测定精子细胞内pH值（pHi）。蛋冻中富集的富硫酸盐糖缀合物可诱导精子中[Ca2+]i和pHi的升高，并诱导顶体反应。精子质膜210 kda糖蛋白外部结构域的单克隆抗体（mab）诱导[Ca2+]i增加23倍（富集硫酸酯糖缀合物为9倍），但单克隆抗体不会导致pHi增加，也不会诱导顶体反应。当诱导[Ca2+]i升高的单抗处理与增加pHi的NH4Cl处理联合使用时，诱导顶体反应。单克隆抗体诱导的[Ca2+]i的增加依赖于细胞外Ca2+的毫浓度，并通过将精子置于无Ca2+的海水中或通过与EGTA螯合Ca2+而逆转。单克隆抗体诱导的[Ca2+]i升高对海水pH敏感，但单克隆抗体的结合不敏感。数据显示，增加的[Ca2+]i和pHi是诱导顶体反应所必需的，并提示210-kDa蛋白可能在调节Ca2+进入精子中起作用。这些单克隆抗体可以将[Ca2+]i的增加从pHi的增加中分离出来，并可能有助于阐明Ca2+在精子生理中的调节作用。
Changes in intracellular free Ca2+ ([Ca2+]i) of sea urchin (Strongylocentrotus purpuratus) spermatozoa were measured using the fluorescent Ca2+ indicators fura-2 and indo-1. The intracellular pH (pHi) of sperm was also determined. The fucose sulfate-rich glycoconjugate component of egg jelly induced increases in [Ca2+]i and pHi in sperm and induced the acrosome reaction. Monoclonal antibodies (mAbs) to external domains of a 210-kDa glycoprotein of the sperm plasma membrane induced a 23-fold increase in [Ca2+]i (vs. 9-fold for fucose sulfate-rich glycoconjugate), but the mAbs did not cause the pHi to increase and did not induce the acrosome reaction. When the mAb treatment which induced an increase in [Ca2+]i was combined with an NH4Cl treatment, which increased the pHi, the acrosome reaction was induced. mAb-induced increases in [Ca2+]i were dependent on millimolar concentrations of extracellular Ca2+ and were reversed by placing sperm in Ca2+-free seawater or by chelating Ca2+ with EGTA. The mAb-induced [Ca2+]i increase was sensitive to the pH of the seawater, although mAb binding was not. The data show that increased [Ca2+]i and pHi are necessary for induction of the acrosome reaction and suggest that the 210-kDa protein may play a role in regulating Ca2+ entry into the spermatozoan. These mAbs make it possible to separate the increase in [Ca2+]i from the increase in pHi and may be useful in the elucidation of the regulatory role of Ca2+ in sperm physiology.