Early Discovery Biochemistry Department, Genentech, South San Francisco, CA, 94080, USA.
Stowers Institute for Medical Research, Kansas City, MO, 64110, USA.
Nat Commun. 2019 Jul 11;10(1):3070. doi: 10.1038/s41467-019-10953-z.
CARD9 and CARD11 drive immune cell activation by nucleating Bcl10 polymerization, but are held in an autoinhibited state prior to stimulation. Here, we elucidate the structural basis for this autoinhibition by determining the structure of a region of CARD9 that includes an extensive interface between its caspase recruitment domain (CARD) and coiled-coil domain. We demonstrate, for both CARD9 and CARD11, that disruption of this interface leads to hyperactivation in cells and to the formation of Bcl10-templating filaments in vitro, illuminating the mechanism of action of numerous oncogenic mutations of CARD11. These structural insights enable us to characterize two similar, yet distinct, mechanisms by which autoinhibition is relieved in the course of canonical CARD9 or CARD11 activation. We also dissect the molecular determinants of helical template assembly by solving the structure of the CARD9 filament. Taken together, these findings delineate the structural mechanisms of inhibition and activation within this protein family.
CARD9 和 CARD11 通过凝聚 Bcl10 聚合来驱动免疫细胞激活，但在受到刺激之前处于自身抑制状态。在这里，我们通过确定包含其半胱天冬氨酸蛋白酶募集结构域（CARD）和卷曲螺旋结构域之间广泛界面的 CARD9 区域的结构，阐明了这种自身抑制的结构基础。我们证明，对于 CARD9 和 CARD11 ，破坏这种界面都会导致细胞过度激活，并导致体外形成 Bcl10 模板化纤维，阐明了 CARD11 许多致癌突变的作用机制。这些结构见解使我们能够描述两种相似但不同的机制，即 CARD9 或 CARD11 激活过程中自身抑制的解除机制。我们还通过解决 CARD9 纤维的结构来剖析螺旋模板组装的分子决定因素。总之，这些发现描绘了该蛋白家族内抑制和激活的结构机制。
