HKR1

HKR1激活Hog1的机理

HKR1（Histidine kinase rhodopsin 1）即组氨酸激酶视紫红质，是一种受光调节的受体组氨酸激酶。它用质子化视网膜希夫碱 (RSB) 辅因子在紫外线吸收状态 (Rh-UV) 和蓝色吸收状态 (Rh-Bl) 之间切换，通过在 13-trans,15-anti 和 13-cis,15 混合物之间切换同分异构体实现。

除此之外，HKR1本身作为一种细胞膜表面受体，属于一种MAPKKK→MAPKK→MAPK通路的起始蛋白质，此处的MAPK是hog1蛋白，目前的研究已表明，HKR1激活hog1蛋白的途径是一种与Msb2激活hog1蛋白相对独立的途径。

参考文献:

Luck Meike., Bruun Sara., Keidel Anke., Hegemann Peter., Hildebrandt Peter.(2015). Photochemical chromophore isomerization in histidine kinase rhodopsin HKR1. FEBS Lett, 589(10), 1067-71. doi:10.1016/j.febslet.2015.03.024

Luck Meike., Mathes Tilo., Bruun Sara., Fudim Roman., Hagedorn Rolf., Tran Nguyen Tra My., Kateriya Suneel., Kennis John T M., Hildebrandt Peter., Hegemann Peter.(2012). A photochromic histidine kinase rhodopsin (HKR1) that is bimodally switched by ultraviolet and blue light. J Biol Chem, 287(47), 40083-90. doi:10.1074/jbc.M112.401604

Nishimura Akiko., Yamamoto Katsuyoshi., Oyama Masaaki., Kozuka-Hata Hiroko., Saito Haruo., Tatebayashi Kazuo.(2016). Scaffold Protein Ahk1, Which Associates with Hkr1, Sho1, Ste11, and Pbs2, Inhibits Cross Talk Signaling from the Hkr1 Osmosensor to the Kss1 Mitogen-Activated Protein Kinase. Mol Cell Biol, 36(7), 1109-23. doi:10.1128/MCB.01017-15

Tatebayashi Kazuo., Tanaka Keiichiro., Yang Hui-Yu., Yamamoto Katsuyoshi., Matsushita Yusaku., Tomida Taichiro., Imai Midori., Saito Haruo.(2007). Transmembrane mucins Hkr1 and Msb2 are putative osmosensors in the SHO1 branch of yeast HOG pathway. EMBO J, 26(15), 3521-33. doi:10.1038/sj.emboj.7601796

Tanaka Keiichiro., Tatebayashi Kazuo., Nishimura Akiko., Yamamoto Katsuyoshi., Yang Hui-Yu., Saito Haruo.(2014). Yeast osmosensors Hkr1 and Msb2 activate the Hog1 MAPK cascade by different mechanisms. Sci Signal, 7(314), ra21. doi:10.1126/scisignal.2004780

Tanaka Keiichiro,Tatebayashi Kazuo,Nishimura Akiko et al. Yeast osmosensors Hkr1 and Msb2 activate the Hog1 MAPK cascade by different mechanisms.[J] .Sci Signal, 2014, 7: ra21.

参考网站：

泛癌分析：http://gepia.cancer-pku.cn/detail.php?gene=hkr1

人体各器官组织表达情况：https://www.proteinatlas.org/ENSG00000181666-HKR1/tissue