Besides a fundamental structural role at the plasma membrane, spectrin‐ and actin‐based skeletons have been proposed to participate in various processes including vesicular trafficking. Neuroendocrine cells release hormones and neuropeptides through calcium‐regulated exocytosis, a process that is coordinated by a fine remodeling of the actin cytoskeleton. We describe here that calcium‐regulated exocytosis is impaired in chromaffin and PC12 cells with reduced αII‐spectrin expression levels. Using yeast two‐hybrid screening, we show that neuronal Wiskott–Aldrich Syndrome protein (N‐WASP) is a partner of the αII‐spectrin SH3 domain and demonstrate that secretagogue‐evoked N‐WASP recruitment at cell periphery is blocked in the absence of αII‐spectrin. Additionally, experiments performed with ectopically expressed αII‐spectrin mutant unable to bind N‐WASP indicated that the interaction between SH3 domain and N‐WASP is pivotal for neuroendocrine secretion. Our results extend the list of spectrin interactors and strengthen the idea that αII‐spectrin is an important scaffold protein that gathers crucial actin‐related players of the exocytic machinery.

中文翻译：

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αII-Spectrin 通过神经元 Wiskott-Aldrich 综合征蛋白相互作用控制神经内分泌嗜铬细胞中钙调节的胞吐作用

除了在质膜上的基本结构作用外，还提出了基于血影蛋白和肌动蛋白的骨架参与包括囊泡运输在内的各种过程。神经内分泌细胞通过钙调节的胞吐作用释放激素和神经肽，这一过程由肌动蛋白细胞骨架的精细重塑协调。我们在这里描述了钙调节的胞吐作用在嗜铬细胞和 PC12 细胞中受损，αII-血影蛋白表达水平降低。使用酵母双杂交筛选，我们表明神经元 Wiskott-Aldrich 综合征蛋白 (N-WASP) 是 αII-Spectrin SH3 结构域的伙伴，并证明在没有αII-血影蛋白。此外，对无法结合 N-WASP 的异位表达的 αII-Spectrin 突变体进行的实验表明，SH3 结构域和 N-WASP 之间的相互作用对于神经内分泌分泌至关重要。我们的结果扩展了 Spectrin 相互作用物的列表，并加强了 αII-Spectrin 是一种重要的支架蛋白的观点，它聚集了胞吐机制的关键肌动蛋白相关参与者。