Proteotyping pluripotency with mass spectrometry.

Pluripotency emerges transiently during embryogenesis in two main forms with different developmental potential, termed naïve and primed states. Importantly, these pluripotent states can be recapitulated in vitro under specific culture conditions, representing a unique model to study the regulatory principles of development and cellular plasticity. Areas covered: A complex network of signaling pathways that senses intrinsic and extrinsic cues controls the fine balance between self-renewal and differentiation. Much of our knowledge on this tight regulation originates from epigenetic and transcriptomic approaches. However, the presence of post-transcriptional and post-translational mechanisms demands a direct assessment of the proteome in its multiple facets. Mass spectrometry-based proteomics is now a mature technique and has started to deliver new insights in the stem cell field. Expert opinion: Here, we review our current understanding on the mechanisms that dictate the spectrum of pluripotency levels. We put special emphasis on the emerging proteomic studies that focused on the molecular properties behind the naïve and primed states. In addition, we hypothesize on the impact that future developments in proteomic technologies can have to improve our view of pluripotency.