Molecular physiology on H^+-translocating vacuolar-type ATPase in silkworms

蚕丝腺（蚕丝蛋白、丝素和丝胶蛋白，工厂）是蚕茧形成过程中独特而不可或缺的组织。腺分泌蚕丝蛋白并将其暂时储存在腺腔内，直到蚕丝开始纺丝。分泌蛋白的浓度可达20-30%。如此高浓度的蛋白质溶液必须用一定的pH值和固定的含水量来调节。我们对这一机制进行了研究，以了解丝腺中离子的稳态和渗透调节。结果如下：(1)用Y-ATPase特异性抗体进行免疫细胞化学研究。在丝腺中可以检测到V-ATFase。V-A-TPase位于细胞表面，说明家蚕的v - atpase属于质膜型而非膜内型。(2)在丝腺中，v - atp酶似乎有助于在腺腔中产生酸性环境。这与鳞翅目中肠腔形成鲜明对比，后者产生。极高的碱度（pH-11-12）。(3)丝腺V-ATPase与其他动物V-ATPase非常相似，具有V-ATPase的共同亚基。(4)蚕丝腺是蚕丝蛋白合成和分泌的高活性组织，v - atp酶必须激活质膜，支持活性氨基酸从血淋巴转运，以合成蚕丝蛋白。因此，对蚕丝中K+/氨基酸同转运体的研究是近期的课题。这将被认为是鉴定K+/对称分子的突破。

The silk gland in silkworms (the silk proteins, fibroin and sericin, factory) is an unique and indispensable tissue to produce the cocoons. The gland secretes and temporally stores the silk proteins within the glandular lumen without any denaturation of proteins till the silkworm starts to spin. The concentrations in the secreted protein reach up to 20-30% levels. Such a high concentration of the protein solution has to be regulated with a certain pH levels and a fixed water contents. We have investigated such a mechanism to understand the- ionic homeostasis and osmoregulation in the silk gland. Results are as-follows :(1) Immunocytochemicat studies were done with the specific antibody against Y-ATPase.. The V-ATFase can be- detected in the silk gland. V-A-TPase was located at the cell surface, suggesting that silkworm V-ATPases is a plasm a membrane-type not an endomanbrane-type.(2) In the silk gland, V-ATPase seems to contribute to produce an acidic milieu in the glandular lumen. This shows highly contrast to the lepidopteran midgut lumen, which produces. an extremely high alkalinity (pH-11-12).(3) The silk gland V-ATPase is quite-similar to other animal V-ATPase sharing the common subuits of V-ATPase.(4) The silk gland is a highly active tissue for silk protein syntesis and secretion The V-ATPase has to energize the plasma membrane and this supports that the active-amino acid transport from the haemolymph in order to synthesize the silkproteiri. Thus it is coming up as the near future subject to survey the K+/amino acid symporter in the silkgland. This would be expected as The breakthrough for identifying the K+/symportev molecule(s).