複合型 GSKIP 在粒線體及 Wnt signal pathway 中的起源和生理功能

The origin and physiological role of composite-type GSKIP- implying in mitochondria and Wnt signaling pathway

林承彥(Chen-Yen Lin)

指導教授 ： 洪義人

高雄醫學大學/醫學院/醫學研究所碩士班/碩士(2020年)

摘要

GSKIP是A-kinase anchoring proteins (AKAP)中最小的一種，並且隱 藏著功能未知的結構域 (Domain Unknown Function 727, DUF727)，且 能演化為 GSK3β 和 PKA 的結合域。本實驗室先前的研究發現哺乳動 物中簡單型 GSKIP (Simple-type GSKIP)的起源，並在 Wnt signal pathway 中扮演清除及競爭者的角色。然而複合型 GSKIP (composite- type GSKIP)的演化機制仍然尚未被了解。在本研究中使用生物資訊 工具，定點突變(site-direct mutagenesis)和酵母雙雜交(yeast-two hybrid) 兩種方法，證明 composite-type GSKIP 經常存在於 clustered mitochondria protein 1 (CLU1) 中 。 除 了 在 GSK3β 結 合 位 (122FXXXLXXR/KL130)外，DUF727 通過側翼區域形成 Pre- GSK3β binding site (115SPXF118)，而在脊椎動物中的 Armadillo repeat- containing protein 4 (ARMC4)中的 SFF103107 側翼區域，僅有 Pre- GSK3β 的結合位點 (115SPX118F)。與 Simple-type GSKIP 比較， GSK3β 結合位序列在 126L 具有 V/I/Q等變體，且 130L 位點在 composite-type GSKIP (CLU1)中均呈現低度保守狀態。這些證據顯示 CLU1 和 ARMC4 可能透過基因融合而來。相反的，在線蟲中 HSP70/DnaK 和 mitofilin 可能透過劫持機制而來。本研究使用 site- direct mutagenesis 和 yeast-two hybrid 實驗，來比較這些 pre-GSK3β
-1-
binding site 在脊椎動物及無脊椎動物中序列的重要性。最終結果顯示 DUF727、pre-GSK3β binding site 和 GSK3β binding sites 的起源，及發 現 CLU1、mitofilin 和 ARMC4 的功能。上述這些基因的演化過程可 能在粒線體和 Wnt signaling pathway 具有重要的功能。

關鍵字

生物資訊 ； DUF-727 ； 複合型 GSKIP ； 粒線體 ； Wnt signaling pathway.

並列摘要

GSK3β interacting protein (GSKIP) is a smallest AKAP protein harboring an uncharacterized Domain Unknown Function 727 (DUF727) with capable of developing GSK3β and PKA binding domains. In our previous study, we unraveled the origin of mammalian simple-type GSKIP during evolution and discovered that it involves in Wnt signaling pathway as a scavenger and competitor. However, the formation of another composite- type GSKIP remains incomplete. In the present study, using bioinformatics tools, site-directed mutagenesis and two-hybrid methods, we demonstrated that composite-type GSKIP frequently existed in clustered mitochondria protein 1 (CLU1) of all eukaryotic organisms. In addition to the consensus sequence GSK3β binding site, 122FXXXLXXR/KL130, it apparently appears that DUF727 domain gradually becomes by forming a pre-GSK3β binding site (115SPXF118) in flanking region, while in vertebrate ARMC4 contains a metaphoric (cryptic) superfamily DUF727 (SSF103107; unintegrated) flanking region with pre-GSK3β binding site 115SPX118F only. Comparative analysis to simple-type GSKIP, GSK3β binding sequence also showed various V/I/Q at 126L, though more surprisingly at 130L which remains un-conserved in all composite-type GSKIP (CLU1). These findings suggest that CLU1 and ARMC4 families evolved may be via a domain-fusion mechanism. On the contrast, the strange order of Hsp70/Dnak and mitofilin in nematode may via a hijack mechanism. Moreover, we performed site-directed mutagenesis and yeast two-hybrid assays to compare and reveal the importance of this pre-GSK3β binding site with its franking GSK3β binding conserved sites within invertebrate
-3-
and vertebrate. Collectively, our data revealed the origin of DUF727, pre- GSK3β binding, GSK3β binding sites and portray the roles of CLU1, mitofilin and ARMC4 genes which could play a vital role in mitochondria and Wnt signaling pathway during evolution.

並列關鍵字

Bioinformatics ； DUF727 ； Composite-type GSKIP ； Mitochondria ； Wnt signaling pathway.

參考文獻

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