Redundancy and Complementarity between ERAP1 and ERAP2 Revealed by their Effects on the Behcet's Disease-associated HLA-B*51 Peptidome
Redundancy and Complementarity between ERAP1 and ERAP2 Revealed by their Effects on the Behcet's Disease-associated HLA-B*51 Peptidome
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DOI：
10.1074/mcp.ra119.001515
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发表时间：
2019-08-01
影响因子：
7
通讯作者：
Lopez de Castro, Jose A.
中科院分区：
文献类型：
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作者：
Guasp, Pablo;Lorente, Elena;Lopez de Castro, Jose A.
HLA-B*51是白塞病的主要危险因素。ERAP 1和ERAP 2修饰肽在内质网中由MHC-I分子呈递。ERAP 1，而不是ERAP 2，也与这种疾病的上位性与B*51。每种或两种酶的抑制允许鉴定这些蛋白质的特定作用及其在形成HLA-B*51肽组上的合作，并为它们与白塞氏病的差异关联提供基础。内质网氨肽酶ERAP 1和ERAP 2修饰肽被装载到HLA分子上，包括白塞氏病的主要危险因子HLA-B*51。ERAP 1也是HLA-B*51阳性个体中的一个风险因素，而与ERAP 2没有关联。本研究探讨了两种酶在HLA结合肽组加工过程中的相互关系，询问了它们与白塞氏病的差异性关联。使用CRISPR/Cas9从转染子721.221-HLA-B*51：01细胞中产生ERAP 1、ERAP 2或两者的敲除。所有病例的HLA-B*51表面表达均降低。通过定量无标记质谱分析耗尽每种或两种酶对B*51：01肽组的影响。观察到肽长度、subpeptidome平衡、N-末端残基使用、亲和力和非典型配体的呈现的大量定量改变。这些影响往往是不同的存在或不存在的其他酶，揭示了它们的相互依赖性。在ERAP 1不存在的情况下，ERAP 2显示出类似的和显著的B*51：01配体加工，表明功能冗余。野生型和双KO细胞的肽组之间的高度重叠表明，即使在不存在ERAP 1/ERAP 2的情况下，大部分B*51：01配体也存在于ER中。这些结果表明，两种酶对B*51：01肽组具有不同但互补和部分冗余的作用，导致其优化和最大表面表达。这两种酶对HLA-B *51肽组的不同作用为它们与白塞氏病的差异性关联提供了基础，并提示B*51：01肽组的致病作用。
HLA-B*51 is the main risk factor for Behcet's disease. ERAP1 and ERAP2 trim peptides in the endoplasmic reticulum to be presented by MHC-I molecules. ERAP1, but not ERAP2, is also associated with this disorder in epistasis with B*51. Inhibition of each or both enzymes allowed the identification of the specific role of these proteins and their cooperation on shaping the HLA-B*51 peptidome and provide a basis for their differential association with Behcet's disease. The endoplasmic reticulum aminopeptidases ERAP1 and ERAP2 trim peptides to be loaded onto HLA molecules, including the main risk factor for Behcet's disease HLA-B*51. ERAP1 is also a risk factor among HLA-B*51-positive individuals, whereas no association is known with ERAP2. This study addressed the mutual relationships between both enzymes in the processing of an HLA-bound peptidome, interrogating their differential association with Behcet's disease. CRISPR/Cas9 was used to generate knock outs of ERAP1, ERAP2 or both from transfectant 721.221-HLA-B*51:01 cells. The surface expression of HLA-B*51 was reduced in all cases. The effects of depleting each or both enzymes on the B*51:01 peptidome were analyzed by quantitative label-free mass spectrometry. Substantial quantitative alterations of peptide length, subpeptidome balance, N-terminal residue usage, affinity and presentation of noncanonical ligands were observed. These effects were often different in the presence or absence of the other enzyme, revealing their mutual dependence. In the absence of ERAP1, ERAP2 showed similar and significant processing of B*51:01 ligands, indicating functional redundancy. The high overlap between the peptidomes of wildtype and double KO cells indicates that a large majority of B*51:01 ligands are present in the ER even in the absence of ERAP1/ERAP2. These results indicate that both enzymes have distinct, but complementary and partially redundant effects on the B*51:01 peptidome, leading to its optimization and maximal surface expression. The distinct effects of both enzymes on the HLA-B*51 peptidome provide a basis for their differential association with Behcet's disease and suggest a pathogenetic role of the B*51:01 peptidome.