Purpose of review Lipid metabolism and de-novo lipogenesis (DNL) is broadly controlled by the SREBP transcription factors. These transcription factors are matured from membrane-anchored precursor proteins by the proteolytic actions of the proteases S1P and S2P. In this review, we summarize the current understanding of SPRING, a recently identified activator of S1P. Recent findings Recent studies of SPRING using animal, cellular, biochemical, and biophysical methods have established SPRING as a core component of the SREBP machinery. Deletion of SPRING in cells and animal livers specifically reduces SREBP activity yet leaves other S1P substrates intact, demonstrating an SREBP-specific role for SPRING in licensing S1P activity. Mechanistic biochemical and structural studies revealed that SPRING activates S1P by competitively displacing its inhibitory pro-domain and elucidated how small molecule inhibition of S1P can be accomplished. Summary Current studies have shown how SPRING activates S1P and uncovered a critical role for SPRING in the SREBP pathway. Further studies are warranted to understand this emerging, connection between SPRING and the regulation of DNL through SREBP.
Micallo et al. (Fri,) studied this question.