Department of Biochemistry and Molecular Biology, Apoptosis and Genomics Research Group, Hungarian Academy of Sciences, University of Debrecen, Nagyerdei krt. 98, Debrecen H-4012, Hungary.
Immunol Lett. 2009 Sep 22;126(1-2):22-8. doi: 10.1016/j.imlet.2009.07.009. Epub 2009 Jul 28.
Transglutaminase 2 (TG2) is a protein crosslinking enzyme with many additional biological functions. We have previously shown that in TG2(-/-) mice the in vivo clearance of apoptotic cells is defective leading to autoimmunity. TG2 contributes to the formation of phagocytic portals by binding to both integrin beta(3), a known phagocytic receptor, and its bridging molecule, MFG-E8. In TG2 null macrophages integrin beta(3) cannot accumulate around the apoptotic cells and its signaling is impaired. In the present study we describe a subline of TG2 null mice, in which a compensatory increase in integrin beta(3) expression, which resulted alone in a high receptor concentration around the apoptotic cells without the requirement for accumulation, partially corrected the defect in integrin beta(3) signaling. Our data provide a proof for the concept that the function of TG2 is to stabilize accumulated integrin beta(3) concentration in the phagocytic cup.
转谷氨酰胺酶 2（TG2）是一种具有许多其他生物学功能的蛋白质交联酶。我们之前已经表明，在 TG2（-/-）小鼠中，细胞凋亡的体内清除存在缺陷，导致自身免疫。TG2 通过与整联蛋白β（3）结合，该分子是一种已知的吞噬受体，以及其桥接分子 MFG-E8，有助于吞噬小窝的形成。在 TG2 缺失的巨噬细胞中，整联蛋白β（3）不能在凋亡细胞周围聚集，其信号转导受损。在本研究中，我们描述了一种 TG2 缺失小鼠的亚系，其中整合素β（3）的表达代偿性增加，这导致凋亡细胞周围的受体浓度很高，而无需积累，部分纠正了整联蛋白β（3）信号转导的缺陷。我们的数据为 TG2 的功能是稳定吞噬小窝中积累的整联蛋白β（3）浓度的概念提供了证据。
