CCAAT/增強子結合蛋白β,簡稱C/EBP-β或CEBPB,是一種在人體中由CEBPB基因編碼的蛋白質。[5][6]
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這種無內含子基因編碼的蛋白質是一種bZIP轉錄因子,可以作為同源二聚體與某些DNA調控區域結合。它還可以與相關蛋白 C/EBP-α、C/EBP-δ和C/EBP-γ形成異二聚體。編碼的蛋白質在調節涉及免疫和炎症反應的基因中很重要,並且已顯示與IL-6基因中的IL-1反應元件以及幾種急性期和細胞因子基因的調節區域結合。此外,編碼的蛋白質可以結合啟動子和上游元件並刺激I型膠原蛋白基因的表達。[7]
CEBPB對正常的巨噬細胞功能至關重要,巨噬細胞是一種重要的免疫細胞亞型;無法表達CEBPB的小鼠具有無法分化(特化)的巨噬細胞,因此無法執行其所有生物學功能——包括巨噬細胞介導的肌肉修復。[8]觀察工作表明,血液白血球中CEBPB的表達與人體肌肉力量呈正相關,[9]強調了免疫系統,特別是巨噬細胞在維持肌肉功能中的重要性。
CEBPB基因的功能可以通過基於獨立驗證的siRNA敲低來有效檢查。[10]
CEBPB能夠增加幾個靶基因的表達。其中,一些在神經系統中具有特定作用,如前速激肽原-1基因,產生P物質和神經激肽A[11]以及負責生物合成重要神經遞質乙酰膽鹼的膽鹼乙酰轉移酶。[12]其他目標包括編碼細胞因子的基因,例如IL-6、[13]IL-4、[14]IL-5、[15]和腫瘤壞死因子-α。[16]還發現編碼賦予細胞多藥抗性的轉運蛋白的基因被CEBPB活化。這樣的基因包括ABCC2[17]和ABCB1。[18]
- Ccaat-enhancer-binding proteins
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