Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK.
Institute of Molecular Cell and Systems Biology, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
J Cell Sci. 2020 Nov 5;133(21):jcs249664. doi: 10.1242/jcs.249664.
Sprouty-2 is an important regulator of growth factor signalling and a tumour suppressor protein. The defining feature of this protein is a cysteine-rich domain (CRD) that contains twenty-six cysteine residues and is modified by S-acylation. In this study, we show that the CRD of sprouty-2 is differentially modified by S-acyltransferase enzymes. The high specificity/low activity zDHHC17 enzyme mediated restricted S-acylation of sprouty-2, and cysteine-265 and -268 were identified as key targets of this enzyme. In contrast, the low specificity/high activity zDHHC3 and zDHHC7 enzymes mediated more expansive modification of the sprouty-2 CRD. Nevertheless, S-acylation by all enzymes enhanced sprouty-2 expression, suggesting that S-acylation stabilises this protein. In addition, we identified two charged residues (aspartate-214 and lysine-223), present on opposite faces of a predicted α-helix in the CRD, which are essential for S-acylation of sprouty-2. Interestingly, mutations that perturbed S-acylation also led to a loss of plasma membrane localisation of sprouty-2 in PC12 cells. This study provides insight into the mechanisms and outcomes of sprouty-2 S-acylation, and highlights distinct patterns of S-acylation mediated by different classes of zDHHC enzymes.
Sprouty-2 是生长因子信号的重要调节剂和肿瘤抑制蛋白。该蛋白的特征是一个富含半胱氨酸的结构域（CRD），其中包含二十六个半胱氨酸残基，并通过 S-酰化修饰。在这项研究中，我们表明 sprouty-2 的 CRD 受到不同 S-酰基转移酶的修饰。高特异性/低活性 zDHHC17 酶介导 sprouty-2 的受限 S-酰化，并且鉴定出半胱氨酸-265 和 -268 是该酶的关键靶标。相比之下，低特异性/高活性 zDHHC3 和 zDHHC7 酶介导 sprouty-2 CRD 的更广泛修饰。尽管如此，所有酶的 S-酰化都增强了 sprouty-2 的表达，表明 S-酰化稳定了该蛋白。此外，我们鉴定出 CRD 中一个预测的 α-螺旋上的两个带电残基（天冬氨酸-214 和赖氨酸-223），它们对于 sprouty-2 的 S-酰化是必需的。有趣的是，扰乱 S-酰化的突变也导致 sprouty-2 在 PC12 细胞中的质膜定位丧失。本研究深入了解 sprouty-2 S-酰化的机制和结果，并突出了不同类型 zDHHC 酶介导的 S-酰化的不同模式。
