Polylysine induces a rapid Ca2+ release from sarcoplasmic reticulum vesicles by mediation of its binding to the foot protein.
Polylysine induces a rapid Ca2+ release from sarcoplasmic reticulum vesicles by mediation of its binding to the foot protein.
复制标题
多聚赖氨酸通过介导其与足蛋白的结合，诱导肌浆网囊泡快速释放 Ca2+。
DOI：
10.1016/0003-9861(89)90515-8
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发表时间：
1989
影响因子：
3.9
通讯作者：
Ikemoto,N
中科院分区：
文献类型：
--
作者：
Cifuentes,ME;Ronjat,M;Ikemoto,N
肌浆网(SR)小泡中加入多聚赖氨酸后，细胞内的钙离子释放迅速，没有明显的滞后期。聚赖氨酸的半最大激活浓度(C12)约为0.99μg/ml，或0.3μm，为文献报道的钙释放诱导剂的最低C12。多聚赖氨酸诱导的钙释放与咖啡因诱导的钙释放具有相似的时程和[Ca2+]依赖性。然而，在较高浓度的聚赖氨酸(例如，10μg/ml)时，几乎没有或几乎没有钙离子释放。用可光交联型放射性标记聚赖氨酸衍生物[~3H]琥珀酰亚胺基叠氮基苯甲酸酯聚赖氨酸光解SR囊泡，分别在激活浓度(3μg/ml)和抑制浓度(10μg/ml)时，将0.28和0.52-1.2mol聚赖氨酸分别与1摩尔的400kDa足蛋白结合。另一方面，与其他SR蛋白结合的聚赖氨酸的量(摩尔/摩尔)可以忽略不计(例如，⩽0.0127摩尔的聚赖氨酸/摩尔钙铁蛋白)。这表明，多聚赖氨酸与足部蛋白的结合不仅是诱导释放的原因，也是失活的原因。这些结果为化学触发钙释放的受体定位于足部蛋白提供了直接证据。抑制多聚赖氨酸诱导的钙释放的钌红不抑制多聚赖氨酸与足部蛋白的结合，提示足部蛋白的多赖氨酸结合区不同于通道区。
The addition of polylysine to a heavy fraction of sarcoplasmic reticulum (SR) vesicles produces a rapid Ca 2+ release with no appreciable lag period. The polylysine concentration for half-maximal activation (C 1 2) is approximately 0.99 μg/ml, or 0.3 μ m, the lowest C 1 2 for Ca 2+ release-inducing reagents reported in the literature. The time course and the [Ca 2+] dependence of polylysine-induced release are similar to those of caffeine-induced Ca 2+ release. At higher concentrations of polylysine (eg, 10 μg/ml), however, little or no Ca 2+ release occurs. Upon photolysis of SR vesicles with the photocrosslinkable radiolabeled polylysine derivative,[3 H] succinimidyl azido benzoate polylysine, 0.28 and 0.52–1.2 mol polylysine were bound to 1 mol of the 400-kDa foot protein at activating (3 μg/ml) and inhibitory (10 μg/ml) concentrations of polylysine, respectively. On the other hand, the amounts of polylysine bound to the other SR proteins (mol/mol) were negligible (eg,⩽ 0.0127 mol polylysine/mol calsequestrin). This suggests that the binding of polylysine to the foot protein is responsible not only for the induction of release but also for inactivation. These results provide direct evidence that the receptor for the chemical trigger of Ca 2+ release is localized within the foot protein. Ruthenium red, which inhibits polylysine-induced Ca 2+ release, does not inhibit polylysine binding to the foot protein, suggesting that the polylysine binding domain of the foot protein is different from the channel domain.