非经典Wnt信号通路

Intracellular signaling of the Wnt pathway diversifies into at least three branches: (1) the β-catenin pathway (canonical Wnt pathway), which activates target genes in the nucleus; (2) the planar cell polarity pathway, which involves jun N-terminal kinase (JNK); and (3) the Wnt/Ca2+ pathway. The last two kinds can be classified into the non-canonical Wnt pathways. In the planar cell polarity pathway, frizzled activates JNK and directs asymmetric cytoskeletal organization and coordinated polarization of cells within the plane of epithelial sheets. This pathway involves the Fmi, Knyand Stbm The Wnt/Ca2+ pathway leads to release of intracellular Ca2+, possibly via G-proteins. This pathway involves activation of PLC and PKC. Elevated Ca2+ can activate the phosphatase calcineurin, which leads to dephosphorylation of the transcription factor NF-AT and its accumulation in the nucleus.