Comparison of the interaction of MKP3 (DUSP6) and its splice variant with ERK by docking methodology

BIGI, MARÍA M.; MORI SEQUEIROS GARCIA MARIA MERCEDES; NUDLER SILVANA; COHEN SABBAN JUAN MANUEL; CORNEJO MACIEL F; MALOBERTI PAULA; PAZ, CRISTINA

Congreso; LXIV Reunión Anual de la Sociedad Argentina de Investigaciones Clínicas.; 2022

MKP-3 is a dual activity enzyme member of the MAP Kinase Phosphatases family. It is induced by proliferative stimuli and specific forphospho-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 proteinregulated by ERK-dependent phosphorylation. S protein lacks thenuclear export signal and a target residue for ERK phosphorylationinvolved in L protein stability. Accordingly, we have demonstrateddifferences 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 topredict 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 absentin S protein. In contrast, S protein retains its binding domain toERK2 through a kinase interaction motif (KIM). We simulated possible interactions between MKP-3 variants and ERK through dockingmethodology. 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, refiningand docking structures 1MKP and 3ZUV. In all cases, the best models obtained achieved a high quality score (CAPRI RANK 3). Theresults suggest that although S protein could interact with ERK, itscatalytic activity would be altered. S protein could act as a negativedominant by interacting through the KIM domain and blocking L interaction with ERK. Based on the analysis and the predictive modelsobtained, our current efforts focus on performing different mutationsand activity measurements on different substrates to validate theseresults.