COMPARISON OF THE INTERACTION OF MKP-3 (DUSP6) AND ITS SPLICE VARIANT WITH ERK BY DOCKING METHODOLOGY

BIGI, MARIA MARCEDES; COHEN SABBAN J.M.; NUDLER, S.; MORI SEQUEIROS GARCÍA, M.M.

Mar del Plata, Buenos Aires, Argentina.

Congreso; Reunión Anual de Sociedades de Biociencias; 2022

Sociedad Argentina de Investigación Clínica. SAIC

MKP-3 is a dual activity enzyme member of the MAP Kinase Phosphatases family. It is induced by proliferative stimuli and specific for phospho-ERK. The human MKP-3 gene generates the full-lengthtranscript or variant L, and an alternative spliced product or variant S, encoding MKP-3S or S protein. MKP-3L is a cytosolic protein regulated by ERK-dependent phosphorylation. S protein lacks the nuclear export signal and a target residue for ERK phosphorylation differences between variants regarding stability, subcellular localization and enzymatic activity measured by ERK dephosphorylation. The aim of this study was to gain insight on MKP-3 spatial structure by a bioinformatic approach to explain these differences and to predict additional functional differences between L and S proteins. From sequence alignments we found that an “acid loop” region,which includes the D262 residue crucial for the catalysis, is absent in S protein. In contrast, S protein retains its binding domain to ERK2 through a kinase interaction motif (KIM). We simulated possible interactions between MKP-3 variants and ERK through docking methodology. From crystals structures 1HZM and 2FYS (PDB IDs) we simulated the ERK interaction with the KIM domain and MKP-3S. Then, we made the prediction of the interaction of the catalytic domain with phosphatase activity and ERK, through aligning, refining and docking structures 1MKP and 3ZUV. In all cases, the best models obtained achieved a high quality score. The results suggest that although S protein could interact with ERK, its catalytic activity would be altered. S protein could act as a negative dominant by interacting through the KIM domain and blocking L interaction with ERK. Based on the analysis and the predictive models obtained, our current efforts focus on performing different mutations and activity measurements on different substrates to validate these results.