There is an increasing appreciation that amino acids can act as signaling molecules in the regulation of cellular processes through modulation of intracellular cell signaling pathways. In culture, embryonic stem (ES) cells can be differentiated to a second, pluripotent cell population, early primitive ectoderm-like cells in response to biological activities within the conditioned medium MEDII. The amino acid L-proline has been identified as a component of MEDII required for ES cell differentiation. Here, we define the primary L-proline transporter on ES and early primitive ectoderm-like cells as sodium-coupled neutral amino acid transporter 2 (SNAT2). SNAT2 uptake of L-proline can be inhibited by the addition of millimolar concentrations of other substrates. The addition of excess amino acids was used to regulate the uptake of L-proline by ES cells, and the effect on differentiation was analyzed. The ability of SNAT2 substrates, but not other amino acids, to prevent changes in morphology, gene expression, and differentiation kinetics suggested that L-proline uptake through SNAT2 was required for ES cell differentiation. These data reveal an unexpected role for amino acid uptake and the amino acid transporter SNAT2 in regulation of pluripotent cells in culture and provides a number of specific, inexpensive, and nontoxic culture additives with the potential to improve the quality of ES cell culture. © 2011 the American Physiological Society.

Item Type:	Refereed Article
Research Division:	Biological Sciences
Research Group:	Biochemistry and Cell Biology
Research Field:	Cell Development, Proliferation and Death
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in the Biological Sciences
Author:	Rathjen, PD (Professor Peter Rathjen)
Author:	Rathjen, J (Dr Joy Rathjen)
ID Code:	78719
Year Published:	2011
Web of Science® Times Cited:	20
Deposited By:	Menzies Institute for Medical Research
Deposited On:	2012-07-24
Last Modified:	2017-11-01
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