Department of Biochemistry, College of Medicine, Inha University, Shinheung-dong, Chung-gu, Incheon, Republic of Korea.
Arch Biochem Biophys. 2012 Jan 1;517(1):37-42. doi: 10.1016/j.abb.2011.11.004. Epub 2011 Nov 11.
FKBP12, an FK506 binding protein, interacts with type 1 ryanodine receptor (RyR1) and modulates its calcium channel activity. However, there are many opposing reports of FKBP12's interaction with other related calcium channels, such as type 1 IP(3) receptor and type 3 ryanodine receptor (IP(3)R1 and RyR3). In addition, the involvement of the prolyl-dipeptide motif in the calcium channels and the corresponding binding residues in FKBP12 remain controversial. Through pulldown assays with recombinant proteins, we provide biochemical evidence of the interaction between FKBP12 and RyR1, RyR3 and IP(3)R1. Using NMR chemical shift mapping, we show that the important binding residues in FKBP12 are located in its hydrophobic FK506 binding region. Consistently, we demonstrate that FK506 can competitively inhibit the interaction between FKBP12 and the dipeptide motifs of the calcium channels. We believe our results shed lights on the binding mechanism of calcium channel-FKBP12 interaction.
FKBP12 是 FK506 结合蛋白，可与肌浆网钙释放通道蛋白 1 型（RyR1）相互作用，并调节其钙通道活性。然而，关于 FKBP12 与其他相关钙通道（如 1 型肌浆网 IP3 受体和 3 型肌浆网钙释放通道）相互作用的报道却有很多争议。此外，脯氨酰二肽基序在钙通道中的作用以及 FKBP12 中的相应结合残基仍存在争议。通过重组蛋白的 pull-down 实验，我们提供了 FKBP12 与 RyR1、RyR3 和 IP3R1 相互作用的生化证据。通过 NMR 化学位移图谱，我们表明 FKBP12 中的重要结合残基位于其疏水性 FK506 结合区域。一致地，我们证明 FK506 可以竞争性抑制 FKBP12 与钙通道二肽基序之间的相互作用。我们相信我们的结果阐明了钙通道-FKBP12 相互作用的结合机制。
