We confirmed that ECAT11 is expressed in early mouse embryos and undifferentiated ES cells. We also found that ECAT11 is rapidly activated during iPSC generation. Despite this specific expression, ECAT11-deficient ES cells were normally self-renewed and remained pluripotent. We were able to generate iPSCs from ECAT11-null fibroblasts. These data demonstrated that ECAT11 is dispensable for the induction and maintenance of pluripotency, despite its specific expression. It has been reported that a lot of truncated sequences derived from L1 are dispersed in the mouse genome, indicating that these fragments might work as complementary factors for ECAT11. Indeed, some dispersed L1 sequences are still active in several types of somatic cells, and germ cells at various developmental stages. L1 expression was also observed in the blastocyst, from which ESCs are derived. The L1ORF1 protein binds to RNA in a sequence non-specific manner. The cytosolic domains of CD79a and CD79b are relatively short intrinsically disordered proteins. Regions in IDPs often demonstrate transient secondary structure formation and different Qingyangshengenin-A segments of a sequence can display a varying degree of secondary structure Crovatin propensity. These regions, demonstrating local structure formation, are usually involved in protein interactions. It is known that IDPs frequently display promiscuity and can have multiple interaction partners. Adaption of IDPs to these often structurally dissimilar partners can be achieved through a process of coupled folding and binding. NMR spectroscopy has proven to be one of the most informative scientific tools to study IDPs and new NMR based methods are continually being developed for this purpose. Chemical shift analysis can be used to probe IDPs for transient secondary structure and thus assist in identifying sites potentially important for interactions. Posttranslational modifications of IDPs are common and often result in a change of the binding affinity for interaction partners. NMR has been extensively used to study phosphorylation of IDPs.