Department of Chemistry, State University of New York at Albany, Albany, New York, USA.
Department of Medicine, Diabetes Research Program, New York University Grossman School of Medicine, New York, New York, USA.
J Biol Chem. 2023 Nov;299(11):105342. doi: 10.1016/j.jbc.2023.105342. Epub 2023 Oct 12.
The diaphanous-related formin, Diaphanous 1 (DIAPH1), is required for the assembly of Filamentous (F)-actin structures. DIAPH1 is an intracellular effector of the receptor for advanced glycation end products (RAGE) and contributes to RAGE signaling and effects such as increased cell migration upon RAGE stimulation. Mutations in DIAPH1, including those in the basic "RRKR" motif of its autoregulatory domain, diaphanous autoinhibitory domain (DAD), are implicated in hearing loss, macrothrombocytopenia, and cardiovascular diseases. The solution structure of the complex between the N-terminal inhibitory domain, DID, and the C-terminal DAD, resolved by NMR spectroscopy shows only transient interactions between DID and the basic motif of DAD, resembling those found in encounter complexes. Cross-linking studies placed the RRKR motif into the negatively charged cavity of DID. Neutralizing the cavity resulted in a 5-fold decrease in the binding affinity and 4-fold decrease in the association rate constant of DAD for DID, indicating that the RRKR interactions with DID form a productive encounter complex. A DIAPH1 mutant containing a neutralized RRKR binding cavity shows excessive colocalization with actin and is unresponsive to RAGE stimulation. This is the first demonstration of a specific alteration of the surfaces responsible for productive encounter complexation with implications for human pathology.
细丝状（F）-肌动蛋白结构组装所需的丝切蛋白相关formin，丝切蛋白 1（DIAPH1）。DIAPH1 是晚期糖基化终产物（RAGE）受体的细胞内效应物，有助于 RAGE 信号转导和效应，例如 RAGE 刺激后细胞迁移增加。DIAPH1 突变，包括其自身抑制域（DAD）的基本“RRKR”基序中的突变，与听力损失、巨血小板减少症和心血管疾病有关。通过 NMR 光谱解析的 N 端抑制域（DID）和 C 端 DAD 之间复合物的溶液结构表明，DID 与 DAD 的碱性基序之间只有短暂的相互作用，类似于在遭遇复合物中发现的相互作用。交联研究将 RRKR 基序置于 DID 的带负电荷的腔中。中和腔导致 DAD 与 DID 的结合亲和力降低 5 倍，缔合速率常数降低 4 倍，表明 RRKR 与 DID 的相互作用形成了有生产性的遭遇复合物。含有中和 RRKR 结合腔的 DIAPH1 突变体与肌动蛋白过度共定位，并且对 RAGE 刺激无反应。这是第一个证明负责与有生产性的遭遇复合物形成相关的表面的特定改变的例子，这对人类病理学有影响。
