Editing Neural plate (section)

===Cell signaling and essential proteins===

Critical to the proper folding and function of the neural plate is N-cadherin, a type of [[cadherin]] protein associated with the nervous system.  N-cadherin is critical to holding neural plate cells together.  Additionally, cells destined to become neural plate cells express nerve cell adhesion molecule (NCAM) to further neural plate cohesion.  Another cadherin, E-cadherin, is expressed by ectodermal cells in the process of neural plate development.<ref name="Gilbert" />

[[File:Protein BMP4 PDB 1reu.png|thumb| 3-D structural model of [[Bone morphogenetic protein 4|BMP-4]]]]
[[Bone morphogenetic protein 4]], or BMP4, is a transforming growth factor that causes the cells of the ectoderm to differentiate into skin cells. Without BMP4 the ectoderm cells would develop into neural cells.  [[Reflection symmetry|Axial]] mesoderm cells under the ectoderm secrete inhibitory signals called [[chordin]], [[Noggin (protein)|noggin]] and [[follistatin]].  These inhibitory signals prevent the action of BMP4, which would normally make the cells ectoderm; as a result, the overlying cells take their normal course and develop into neural cells.  The cells in the ectoderm that circumscribe these neural cells do not receive the BMP4 inhibitor signals and as a result BMP4 induces these cells to develop into skin cells.<ref>{{cite journal|last=Wilson|first=PA|author2=Lagna, G |author3=Suzuki, A |author4= Hemmati-Brivanlou, A |title=Concentration-dependent patterning of the Xenopus ectoderm by BMP4 and its signal transducer Smad1.|journal=Development|date=Aug 1997|volume=124|issue=16|pages=3177–84|doi=10.1242/dev.124.16.3177 |pmid=9272958}}</ref>

Neural plate border specifiers are induced as a set of transcription factors. Distalless-5, [[PAX3]] and [[PAX7]] prevent the border region from becoming either neural plate or epidermis.<ref name="Gilbert" /> These induce a second set of transcription factors called neural crest specifiers, which cause cells to become [[neural crest cells]].

In a newly formed neural plate, PAX3 mRNA, [[MSX1]] mRNA, and MSX1/MSX2 proteins are expressed mediolaterally.<ref name=Liem>{{cite journal|last=Liem|first=Karel F|author2=Tremml, Gabi |author3=Roelink, Henk |author4= Jessell, Thomas M |title=Dorsal differentiation of neural plate cells induced by BMP-mediated signals from epidermal ectoderm|journal=Cell|date=1 September 1995|volume=82|issue=6|pages=969–979|doi=10.1016/0092-8674(95)90276-7|pmid=7553857|s2cid=17106597|doi-access=free}}</ref>  When the neural plate begins to fold, rostral areas of the neural plate do not express Pax3 and MSX proteins. Areas caudal to [[neural tube]] closure have PAX3 and MSX expression restricted to lateral regions of the neural folds.<ref name="Liem" /> These fluctuations in mRNA and protein expression allude to how they play a role in differentiation of neural plate cells.

Low pSMAD 1, 5, 8 levels allow a greater mobility at the median hinge point than in lateral neural plate cells.<ref>{{cite journal|last=Eom|first=Dae S|author2=Amarnath, Smita |author3=Agarwala, Seema |title=Apicobasal Polarity and neural tube closure|journal=Development, Growth & Differentiation|date=20 December 2012|volume=55|issue=1|pages=164–172|doi=10.1111/dgd.12030|pmid=23277919|pmc=3540145}}</ref> This flexibility allows for the pivoting and hinging that allows the buckling and lifting of the neural plate when formatting the neural tube. The neural plate has to be rigid enough for morphogenic movements to occur while being flexible enough to undergo shape and position changes for the transformation to the neural tube.