Elucidating the Effect of the MK-STYX KIM Domain Mutation on Docking to MAPK
Zmuda, Zoe
Zmuda, Zoe
Abstract
Pseudophosphatase MK-STYX [MAPK (mitogen-activated protein kinase) phosphoserine/threonine/tyrosine-binding protein] is a pseudophosphatase of the MAPK phosphatase (MKP) family that lacks catalytic activity due to key mutations in its dual-specificity phosphatase (DUSP) domain. MK-STYX also has mutations in its kinase interaction motif (KIM). Active phosphatases MKP-1 and MKP-3 contain two conserved arginine residues in their KIM essential for MAPK binding. MK-STYX possesses only one, potentially disrupting interaction with MAPKs such as ERK1/2. To investigate whether introducing these consecutive arginine residues back into the KIM of MK-STYX would restore MAPK binding, different MK-STYX variants, MK-STYX V53R, MK-STYX RR, and MK-STYX RRR were generated. Co-immunoprecipitation and immunoblots were performed on HEK293 cells co-expressed with MK-STYX constructs and ERK1/2 to assess protein-protein interactions. All constructs showed similarly low levels of ERK1/2 binding, suggesting that restoring the canonical arginine residues in the KIM domain is not sufficient to induce binding. These results support reports that the role of MK-STYX as a regulator is independent of the ERK1/2 signaling pathway. In addition, these studies provide a basis for further investigating additional key residues and molecular interactions that affect KIM domain-mediated docking. Despite lacking phosphatase activity, MK-STYX plays critical roles in regulation of pathways, such as apoptosis and neurite formation, as well as disease development, such as various cancers and diabetes. A deeper understanding of the KIM’s binding mechanism is crucial to learning more about how MK-STYX functions, and how it can be utilized in other contexts, such as general medicine and pharmaceutical research.
Description
Date
2026
Journal Title
Journal ISSN
Volume Title
Publisher
Collections
Download Dataset
Files
Zoe_Zmuda_Thesis.docx
Microsoft Word XML, 1.48 MB
- Embargoed until 2032-05-05
Rights Holder
The author
Usage License
Embargo
2032-05-05
Research Projects
Organizational Units
Journal Issue
Keywords
Citation
Department
Biology