Table 4.

Signaling pathways and signaling molecules involved in regulating growth and differentiation in the embryonic NSC niche

Category	Type	Notes & comments	References
Signaling pathway components	MAPK/Erk	proliferation of NSC; neural specification of ES cells requires Erk1/2 activation (while p38-MAPK inhibits NSC proliferation)	Campos et al. 2004 [29], 2006 [150]; Stavridis et al. 2007 [147]; Learish et al. 2000 [144]
	Notch	deficiency in components of notch signaling pathway (Hes1, Notch-1, RBP-Ik, PS1) decreases NSC number; required for NSC proliferation, regulates neuronal versus glial fate specification	Nakamura et al. 2000 [149]; Hitoshi et al. 2002 [148];
	FAK	interkinetic nuclear migration and planar division of neuroepithelia; adhesion during radial glial-mediated neuronal migration	Tsuda et al. 2010 [130]; Valiente et al. 2011 [116]
	Rac1	deficiency in rac1 causes reduction of neural progenitors and microcephaly in mice	Chen et al. 2008 [153]
	Cdc42	maintenance of apical-basal polarity and NSC self-renewal	Cappello et al. 2006 [154]
	Hippo	Yap1/TEAD (downstream targets of Hippo/Mst1/2) regulate neural progenitor numbers in the chick	Cao et al. 2008 [136]
	mTOR	as a potential target of cdc42 might induce NSC proliferation	Magri et al. 2011 [155]