TY - JOUR A1 - Zöller, Tobias A1 - Wittenbrink, Mareike A1 - Hoffmeister, Meike A1 - Steinle, Alexander T1 - Cutting an NKG2D ligand short : cellular processing of the peculiar human NKG2D ligand ULBP4 T2 - Frontiers in immunology N2 - Stress-induced cell surface expression of MHC class I-related glycoproteins of the MIC and ULBP families allows for immune recognition of dangerous “self cells” by human cytotoxic lymphocytes via the NKG2D receptor. With two MIC molecules (MICA and MICB) and six ULBP molecules (ULBP1–6), there are a total of eight human NKG2D ligands (NKG2DL). Since the discovery of the NKG2D–NKG2DL system, the cause for both redundancy and diversity of NKG2DL has been a major and ongoing matter of debate. NKG2DL diversity has been attributed, among others, to the selective pressure by viral immunoevasins, to diverse regulation of expression, to differential tissue expression as well as to variations in receptor interactions. Here, we critically review the current state of knowledge on the poorly studied human NKG2DL ULBP4. Summarizing available facts and previous studies, we picture ULBP4 as a peculiar ULBP family member distinct from other ULBP family members by various aspects. In addition, we provide novel experimental evidence suggesting that cellular processing gives rise to mature ULBP4 glycoproteins different to previous reports. Finally, we report on the proteolytic release of soluble ULBP4 and discuss these results in the light of known mechanisms for generation of soluble NKG2DL. KW - NKG2D KW - ULBP4 KW - NK cells KW - shedding KW - antibodies Y1 - 2018 UR - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/46496 UR - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-464967 SN - 1664-3224 N1 - Copyright: © 2018 Zöller, Wittenbrink, Hoffmeister and Steinle. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. VL - 9 IS - Art. 620 SP - 1 EP - 11 PB - Frontiers Media CY - Lausanne ER -