ASAP1 and its paralog ASAP2 belong to a PI4,5P2-dependent Arf GTPase-activating protein (Arf-GAP) family capable of modulating membrane and cytoskeletal dynamics. ASAPs regulate cell adhesive structures such as invadosomes and focal adhesions during cell attachment and migration. Malfunctioning of ASAP1 has been implicated in the malignant phenotypes of various cancers. Here, we discovered that the SH3 domain of ASAP1 or ASAP2 specifically binds to a 12-residue, positively charged peptide fragment from the 440 kDa giant ankyrin-B, a neuronal axon specific scaffold protein. The high-resolution structure of the ASAP1-SH3 domain in complex with the gAnkB peptide revealed a noncanonical SH3-ligand binding mode with high affinity and specificity. Structural analysis of the complex readily uncovered a consensus ASAP1-SH3 binding motif, which allowed the discovery of a number of previously unknown binding partners of ASAP1-SH3 including Clasp1/Clasp2, ALS2, β-Pix, DAPK3, PHIP, and Limk1. Fittingly, these newly identified ASAP1 binding partners are primarily key modulators of the cytoskeletons. Finally, we designed a cell-penetrating, highly potent ASAP1 SH3 domain binding peptide with a Kd ∼7 nM as a tool for studying the roles of ASAPs in different cellular processes.

中文翻译：

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源自 ASAP1/440-kD 锚蛋白-B 相互作用的结构表征的 ASAP Arf-GAPs 的新靶点和设计抑制剂


ASAP1 及其旁系同源物 ASAP2 属于 PI4,5P2 依赖性 Arf GTP 酶激活蛋白 （Arf-GAP） 家族，能够调节膜和细胞骨架动力学。ASAP 在细胞粘附和迁移过程中调节细胞粘附结构，例如侵袭体和黏着斑。ASAP1 功能障碍与各种癌症的恶性表型有关。在这里，我们发现 ASAP1 或 ASAP2 的 SH3 结构域特异性结合来自 440 kDa 巨型锚蛋白-B（一种神经元轴突特异性支架蛋白）的 12 个残基、带正电荷的肽片段。与 gAnkB 肽复合的 ASAP1-SH3 结构域的高分辨率结构揭示了一种具有高亲和力和特异性的非经典 SH3 配体结合模式。复合物的结构分析很容易发现一个共有的 ASAP1-SH3 结合基序，这允许发现许多以前未知的 ASAP1-SH3 结合伴侣，包括 Clasp1/Clasp2、ALS2、β-Pix、DAPK3、PHIP 和 Limk1。恰如其分地，这些新发现的 ASAP1 结合伴侣主要是细胞骨架的关键调节剂。最后，我们设计了一种 Kd ∼ 7 nM 的细胞渗透性强、高效的 ASAP1 SH3 结构域结合肽，作为研究 ASAP 在不同细胞过程中的作用的工具。