分子细胞生物学：小肠上皮更新自稳信号调控

1、Signal RegulationIn the case of small intestinal epitheliumFirst,lets see the structure of Intestinal Epithelium.Three Region（Layer） Stem cell Region：Stem cells，Paneth Cells TA Region：TA cells（transit amplifying cells，过渡扩增细胞） Differentiated Region：Four Signal Pathways Wnt； Notch； EGF（Epithelial Grow

2、th Fector，上皮生长因子）； BMP（Bone Morphogenesis Protein骨形态发生蛋白） What if I am a intestinal cell? XD Born from a stem sell. move to TA region(My fate will be chosen here) back to stem cell region to be a Paneth cell?or go upward to be a functional cell(and die soon)? What kind of functional cell would I be?

3、 Secreting cell?Absorbing cell?Wnt c-Myc Promote Wnt EphB- Ephrin B self-renewing multiplication Sox9 maturity of Paneth cell intestinal stem cells Paneth cell intestinal stem cells BMP (transforming growth factor-, TGF-) mesenchymal cells in villusmesenchymal cells around the recessBMP2,BMP4cells i

4、n the base layer of the recesscells around the recessNoggin .ChordininhabitInhibits self-renewing and multiplicationinhibit Notch (cell-cell)ligands (Jagged1, Jagged3, Dll1, Dll3,Dll4)combine receptors (Notch1, Notch2, Notch3 , Notch4)release NCID,(Notch intracellular domin)enter the nucleus and com

5、bine Rbpj(recombination signal binding protein for immunoglobulin kappa J region)transcriptioninhibits differentiation of secretory type cells and promote differentiation of absorption-type cellsEGF (growth factor)ligands combine with receptors(EGFR, ErbB-2, ErbB-3,ErbB-4)activate the signaling pathway(PI3K/Akt, PLC/ PKC and Ras/Raf/Mek/