Signaling pathways dictating pluripotency in embryonic stem cells.

Embryonic Stem Cells (ESCs) are derived from the inner cell mass of blastocysts. They have the unique potency to differentiate into diverse lineages. Hence, they are bestowed with the term pluripotency. Several mechanisms have been implicated in maintaining the pluripotency of ESCs. This review will focus on the role of signaling pathways in regulating ESC pluripotency among diverse mammalian species. A novel phylogenetic approach has been designed to understand the structural basis of divergence in the signaling pathways which modulate pluripotency among different species. Detailed insight into different signaling mechanisms indicates inhibition of Extracellular Related Kinase 1/2 (ERK 1/2) signaling as the key component regulating the pluripotency of ESCs. On the basis of recent advances made in this field, it can be hypothesized that expression of the transcription factor KLF4 and inhibition of ERK signaling may promote the establishment and maintenance of true ESCs from different mammalian species.