NSF Postdoctoral Fellowship in Biology: Illuminating mechanisms of essential asparagine-linked glycosylation enzymes

Ochoa, Jessica Micaela, Pasadena CA

Investigators

Abstract

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2023, Broadening Participation of Groups Underrepresented in Biology. The Fellowship supports a research and training plan for the Fellow that will increase the participation of groups underrepresented in biology. Amino acids are one of the essential building blocks of life. All cells use amino acids to create larger, more complex structures called proteins, with several requiring additional changes to ensure proper function. In some proteins, one such change involves the attachment of complex sugar molecules to specific amino acids; this process is called glycosylation. Once attached, these sugars play roles in controlling how proteins function and how proteins interact with other molecules. Without glycosylation, proteins would function improperly, disrupting essential biological functions. In humans, this can lead to numerous congenital disorders and cancers. Despite its critical role, little is understood about how the complex sugars used in glycosylation are generated. Thus, this research seeks to investigate the enzymes that make these sugars; this work explores enzyme function by understanding their molecular structures. Because glycosylation is important for all life, understanding these enzymes will create new insights that guide future applications in biotechnology, including designing new therapeutics that target congenital disorders of glycosylation and cancers. Moreover, this work will facilitate the fellow’s ability to directly train and mentor diverse trainees navigating their own scientific careers. This work will enrich foundational knowledge of asparagine-linked glycosylation (NLG) by defining broad catalytic mechanisms of phosphotransferases and glycosyltransferases, and formulating underlying principles applicable to NLG in all domains of life. Using recombinant protein expression in human cells, structural biology, bioinformatics, and biochemistry, this work will fully characterize the human phosphotransferase, DPATG1, and its partner glycosyltransferases Alg13 and Alg14. This work will also investigate novel interactions between other essential NLG glycosyltransferases. To achieve this, the fellow will determine the structure of human DPAGT1 in complex with novel inhibitors by cryo-EM. Then, the fellow will structurally characterize the DPAGT1/Alg13/Alg14 complex. Lastly, the fellow will leverage AlphaFold to probe uncharacterized heterooligomeric complexes and define universal mechanisms of integral membrane phosphotransferases and glycosyltransferases from the NLG pathway. The fellow will attend cryo-EM training workshops and field-specific conferences. Lastly, the fellow will build upon existing infrastructure to create a campus-wide network for students and postdocs from historically marginalized backgrounds that seeks to build community, professional development, and connect trainees with existing resources. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.