6月14日，Structure雜志在線報道了與心衰等多種重要疾病相關(guān)的生物堿利阿諾定受體（RyR）結(jié)構(gòu)的最新研究進展,。RyR是一類位于內(nèi)質(zhì)網(wǎng)膜上的鈣離子釋放通道,，常作為磷酸化和疾病突變的靶點,。
該研究揭示了三種RyR異構(gòu)體（RyR1-3）的一個關(guān)鍵的磷酸化靶點結(jié)構(gòu)域的晶體結(jié)構(gòu),。該結(jié)構(gòu)域含有Ser2843 (RyR1) 和Ser2808/Ser2814 (RyR2)磷酸化位點。RyR1中磷酸化靶點結(jié)構(gòu)域是11種疾病突變的靶點,。其中一些突變聚集在磷酸化位點的附近,，這提示磷酸化和疾病突變可能影響同一蛋白結(jié)構(gòu)界面。L2867G突變可導(dǎo)致蛋白熱力學(xué)極大的不穩(wěn)定及室溫條件下的聚集,。其他疾病突變體的晶體結(jié)構(gòu)顯示,，這些突變影響蛋白表面特性和結(jié)構(gòu)域內(nèi)鹽橋。
體外磷酸化實驗顯示,，在RyR2的一個長環(huán)結(jié)構(gòu)中有多達5個氨基酸殘基可被PKA或鈣調(diào)蛋白II所磷酸化,。為確定磷酸化靶點結(jié)構(gòu)域在RyR三維結(jié)構(gòu)中的位置，研究者將晶體結(jié)構(gòu)接合為低溫電子顯微圖,，發(fā)現(xiàn)在RyR蛋白的鉗狀區(qū)域有一個假定的位點,。這提示突變和磷酸化可影響此區(qū)域內(nèi)的變構(gòu)運動。
利阿諾定受體結(jié)構(gòu)信息的進一步闡明可為針對心衰等疾病的藥物研發(fā)提供更多的參考,。(生物谷bioon.com)
doi:10.1016/j.cell.2011.10.017
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Disease Mutations in the Ryanodine Receptor Central Region: Crystal Structures of a Phosphorylation Hot Spot Domain
Zhiguang Yuchi, Kelvin Lau, Filip Van Petegem
Ryanodine Receptors (RyRs) are huge Ca2+ release channels in the endoplasmic reticulum membrane and form targets for phosphorylation and disease mutations. We present crystal structures of a domain in three RyR isoforms, containing the Ser2843 (RyR1) and Ser2808/Ser2814 (RyR2) phosphorylation sites. The RyR1 domain is the target for 11 disease mutations. Several of these are clustered near the phosphorylation sites, suggesting that phosphorylation and disease mutations may affect the same interface. The L2867G mutation causes a drastic thermal destabilization and aggregation at room temperature. Crystal structures for other disease mutants show that they affect surface properties and intradomain salt bridges. In vitro phosphorylation experiments show that up to five residues in one long loop of RyR2 can be phosphorylated by PKA or CaMKII. Docking into cryo-electron microscopy maps suggests a putative location in the clamp region, implying that mutations and phosphorylation may affect the allosteric motions within this area.
