Loy Cody A, Trader Darci J
Department of Pharmaceutical Sciences, University of California Irvine California 92617 USA
RSC Chem Biol. 2024 Jul 16;5(9):877-883. doi: 10.1039/d4cb00148f. eCollection 2024 Aug 28.
The immunoproteasome (iCP) can be expressed under inflammatory conditions, such as exposure to interferon-gamma (IFN-γ), that alerts the cell to begin generating iCP preferentially over the standard proteasome (sCP). With the iCP becoming a widely targeted isoform in a variety of diseases, there is a need to understand its activity and expression in cells and Activity-based probes for the iCP have been developed but their application has been limited due to their difficult synthesis and cannot be used in tissues or whole animals. Our lab has previously demonstrated we can monitor iCP activity using a 4-mer peptide linked to a fluorophore and a peptoid. This was utilized in the development of the first cell-permeable iCP activity-based probe that did not include a covalent reactive moiety. Here, we demonstrate that this same peptide recognition sequence can be appended to aminoluciferin, caging it, until its interaction with the iCP. This probe should be applicable to monitor iCP activity in animal models where tumor or other tissue has been engineered to produce luciferase. We anticipate it could also be applied to observe iCP activity as tumors are formed .
免疫蛋白酶体（iCP）可在炎症条件下表达，如暴露于γ干扰素（IFN-γ）时，它会提醒细胞优先于标准蛋白酶体（sCP）开始生成iCP。由于iCP在多种疾病中成为广泛靶向的异构体，因此有必要了解其在细胞中的活性和表达情况。已开发出基于活性的iCP探针，但由于其合成困难且不能用于组织或完整动物，其应用受到限制。我们实验室之前已证明，我们可以使用与荧光团和类肽连接的四聚体肽来监测iCP活性。这被用于开发第一种基于细胞渗透性的iCP活性探针，该探针不包含共价反应性部分。在此，我们证明相同的肽识别序列可以附加到氨基荧光素上，将其封闭，直到它与iCP相互作用。该探针应适用于监测动物模型中的iCP活性，在这些模型中肿瘤或其他组织已被改造以产生荧光素酶。我们预计它也可用于观察肿瘤形成过程中的iCP活性。
