Bioinformatics Approach to Understand the Dynamics of Mms21 SUMO Ligase and Sumoylated Protein Complexes

Emily Jones, Allison Williams, Haley Stabile, and Yee Mon Thu, Department of Biology and Biochemistry, Allegheny College, 520 North Main Street, Meadville PA 16335

Responding to DNA damage is crucial for genome integrity. Sumoylation, a process in which a SUMO peptide or chain is covalently linked at SUMO-consensus sites of a target protein, regulates DNA repair and response proteins. Multiple proteins from the same functional complex are sumoylated by SUMO ligases which can localize to the site of damage. The interaction between SUMO covalently linked to the target and SUMO-interacting motifs (SIMs) of its binding partners strengthens protein complexes. To understand the dynamics of E3 SUMO ligase Mms21 and its targets in response to methyl methanesulfonate (MMS), a DNA damaging agent, we used existing mass spectrometry studies in Saccharomyces cerevisiae. We determined 1) if the composition of Mms21 targets can reveal its localization and 2) if proteins in complex with sumoylated proteins harbor more SIMs. Gene ontology (GO) analysis of Mms21 targets in MMS treated and untreated cells suggest that Mms21 is typically localized to chromosomes. GO analysis also suggests that once cells are treated with MMS, Mms21 relocalizes to the transmembrane/plasma membrane. To address the second question we used reported Mms21 targets in MMS treated cells and determined which protein complexes they belong to. We identified SIMs and SUMO consensus sites in all members of protein complexes whose members are sumoylated or not sumoylated using GPS-SUMO ( We found that the number of SIMs is comparable between the two groups. Individual members of the protein complexes in which at least one protein is sumoylated have more SIMs and SUMO consensus sites compared to their counterparts in the complexes without any sumoylated members. This implies that more than one SIM/SUMO consensus site may be necessary for sumoylation. We will use additional mass spectrometry studies to confirm our results and investigate the localization of Mms21 in S. cerevisiae. 

Additional Abstract Information

Presenter: Emily Jones

Institution: Allegheny College

Type: Poster

Subject: Biology

Status: Approved

Time and Location

Session: Poster 3
Date/Time: Mon 4:30pm-5:30pm
Session Number: 3044