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Figure 1
Putative role of  -catenin in stem-cell renewal and maintenance
through cadherin-containing adherens junctions and Wnt signalling. Support
cells such as CAP cells, inner sheath cells or spindle-shaped
N-cadherin+CD45- osteoblastic (SNO) cells
form adherens junctions with germline stem cells, somatic stem cells or
haematopoietic stem cells (HSCs), respectively, through E-cadherin or
N-cadherin and -catenin (Lin, 2002). In
addition, -catenin can be stabilized as a result of Wnt signalling
through the frizzled (Fzd) receptors leading to the inhibition of the
APC–axin–GSK3- complex, allowing transcriptional activation
of target genes by T-cell factor (TCF)/-catenin complexes.
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Figure 2
Signalling pathways and transcription factors involved in the
maintenance, proliferation, survival and differentiation of embryonic stem (ES)
cells and embryonic germ (EG) cells. LIF,leukaemia inhibitory factor; PTEN,
phosphatase and tensin homologue; PI(3)K, phosphatidylinositol-3-OH-kinase;
Stat3, signal transducer and activator of transcription 3.
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