Studies on the Interaction of Zinc and SAP102 N-Terminus

Dominique De Los Reyes, Yonghong Zhang, University of Texas Rio Grande Valley 1201 W University Dr. Edinburg, TX 78539

Synapse-associated protein 102 (SAP102) is a postsynaptic scaffolding protein within the membrane-associated guanylate kinase (MAGUK) family of proteins. It plays a primary role in synaptic development and maturation. SAP102 mediates trafficking of AMPA receptors and NMDA receptors during the early stage of synapse maturation, exhibits unique and high synaptic mobility, which, however, remains elusive. Unlike postsynaptic density protein 95 (PSD95), another protein within the MAGUK family, much is still unknown about SAP102. Since SAP102 mutations have been linked to intellectual disabilities in humans, it is important to learn more about this protein. Intriguingly, the N-terminal domain of SAP102 contains a zinc finger motif. The function of this motif is unknown yet, therefore this research aimed to disvoer whether the zinc ion could act as a modulator for SAP102 and bind to its N-terminal. We performed structural studies on the zinc finger domain using fluorescence spectroscopy and NMR techniques. The DNA plasmids of SAP102 N-terminus (SAP102NT) were constructed, and the recombinant SAP102NT proteins were expressed and purified by affinity and gel filtration chromatography. The zinc binding with SAP102NT was determined by fluorescence and NMR titration, and further confirmed by mutagenesis. Our results show that zinc binds tightly to the N-terminus of SAP102 with a binding affinity in the micromolar range, suggesting that zinc is likely to serve a functional modulator of SAP102 at synaptic sites.

Additional Abstract Information

Presenter: Dominique De Los Reyes

Institution: University of Texas Rio Grande Valley

Type: Poster

Subject: Biochemistry

Status: Approved

Time and Location

Session: Poster 1
Date/Time: Mon 1:30pm-2:30pm
Session Number: 2135