NANOG

What is NANOG protein?

NANOG (Nanog homeobox) gene is a protein coding gene which situated on the short arm of chromosome 12 at locus 12p13. NANOG (Homeobox protein NANOG) is a member of the Nanog homeobox family of DNA-binding proteins. It is expressed in embryonic stem cells and confers pluripotency on these cells. Once embryonic stem cells become differentiated, NANOG expression is suppressed. NANOG is involved in the Hedgehog/Gli1 signaling pathway which has been implicated in the development and growth of various types of tumors. The NANOG protein is consisted of 305 amino acids and its molecular mass is approximately 34.6 kDa.

What is the function of NANOG protein?

NANOG acts as a transcriptional activator or repressor involved in inner cell mass and embryonic stem (ES) cells proliferation and self-renewal. It imposes pluripotency on ES cells and prevents their differentiation towards extraembryonic endoderm and trophectoderm lineages. And NANOG can also block bone morphogenetic protein-induced mesoderm differentiation of ES cells by physically interacting with SMAD1 and interfering with the recruitment of coactivators to the active SMAD transcriptional complexes.

NANOG Related Signaling Pathway

By interacting with multiple signaling pathways, such as Wnt/β-catenin signaling pathway, TGF-β/BMP signaling pathway, Hippo/YAP signaling pathway, Oct4/Sox2 signaling pathway, etc., NANOG is involved in multiple biological processes such as self-renewal, pluripotency maintenance and cell fate determination of stem cells.

NANOG Related Diseases

NANOG protein is an important transcription factor associated with the maintenance of self-renewal and pluripotency of embryonic stem cells. Nanog protein is abnormally expressed in some tumors, including gastric cancer, lung cancer, breast cancer, ovarian cancer and colorectal cancer. Abnormal expression of NANOG may lead to impaired function of germ cells, resulting in infertility, or affect embryonic development and stem cell diseases.

Fig1. Paradoxical effects of EVs from Nanog-overexpressing cancer cells on their metastasis. (Mikako Saito, 2022)

Bioapplications of NANOG

NANOG is a major marker of stem cells, especially embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). The self-renewal ability and pluripotency of stem cells can be assessed by detecting the expression level of NANOG protein. By regulating the expression of Nanog protein, the differentiation and development of stem cells can be promoted, which can be used to treat certain diseases.

Case study 1: Hee Yun, 2022

NANOG engages with tumour initiation and metastasis by regulating the epithelial-mesenchymal transition (EMT) in epithelial ovarian cancer (EOC). However, its role in association with pAMPKα, and its clinical significance in EOC have not been elucidated even though AMPK is known to degrade NANOG in various human cancers. Hence, this team investigated the role of pAMPKα and its association with NANOG as potential prognostic biomarkers in EOC.

Both NANOG and pAMPKα expression were significantly overexpressed in EOCs comparing nonadjacent normal epithelial tissues, benign tissues, and borderline tumours. In ovarian cancer cell lines, siRNA-mediated NANOG knockdown diminished migration and invasion properties by regulating the EMT process via the AMPK/mTOR signalling pathway.

Fig1. Protein expression of NANOG and α-actinin was analysed by western blot (numbers below each blot are densitometric values).

Fig2. Inhibition of the AMPK signalling pathway reverses the effect of NANOG knockdown on EMT.

Case study 2: Kyoung-Jae Choi, 2022

Human NANOG expression resets stem cells to ground-state pluripotency. Here this team identified the unique features of human NANOG that relate to its dose-sensitive function as a master transcription factor.

Full-length NANOG readily forms higher-order oligomers at low nanomolar concentrations, orders of magnitude lower than typical amyloids. Using single-molecule Förster resonance energy transfer and fluorescence cross-correlation techniques, the researchers show that NANOG oligomerization is essential for bridging DNA elements in vitro. Using chromatin immunoprecipitation sequencing and Hi-C 3.0 in cells, we validate that NANOG prion-like domain assembly is essential for specific DNA recognition and distant chromatin interactions. NANOG's unique ability to form prion-like assemblies could provide a cooperative and concerted DNA bridging mechanism that is essential for chromatin reorganization and dose-sensitive activation of ground-state pluripotency.

Fig3. Autocorrelation FCS curves of (i) h6g-eGFP and GFP-tagged NANOG WT and W8A constructs (~10 nM) in HEK 293T mammalian cell lysates.

Fig4. smFRET of ~100 pM each of Gata6-AF488 and Gata6-AF647 intermolecular diffusion in (i) the absence or (ii,iii) the presence of 250 nM NANOG W8A or WT NANOG.

NANOG has several biochemical functions, for example, DNA binding,sequence-specific DNA binding,transcription corepressor activity. Some of the functions are cooperated with other proteins, some of the functions could acted by NANOG itself. We selected most functions NANOG had, and list some proteins which have the same functions with NANOG. You can find most of the proteins on our site.

NANOG has direct interactions with proteins and molecules. Those interactions were detected by several methods such as yeast two hybrid, co-IP, pull-down and so on. We selected proteins and molecules interacted with NANOG here. Most of them are supplied by our site. Hope this information will be useful for your research of NANOG.