Determining the Role MK‐STYX plays in Autophagy in Regard to LC3B Expression

Abstract

Cellular processes are maintained at maximum efficiency by ridding cells of redundant and extraneous organelles, proteins, and other cellular compounds. Components of these cellular processes are not completely lost. Rather, they can be recycled into new materials, a cellular recycling system driven by autophagy (specifically macroautophagy). Autophagy has been reported to clear stress granules, aggregations of stalled mRNA, which are toxic to the cell at high concentrations. MK‐STYX [mitogen‐activated protein kinase (MAPK) phosphoserine/threonine/tyrosine‐binding protein] has also been reported to clear stress granules. MK‐STYX is an atypical member of the protein tyrosine phosphatase (PTP) superfamily, because its catalytic signature motif does not contain the essential nucleophilic cysteine required for catalytic activity. The correlation that stress granules decrease through MK‐STYX and/or autophagy provides a foundation for this research. We are investigating the role of pseudophosphatase MK‐STYX in autophagic pathways via its effects on the expression of the autophagosome‐promoting protein, LC3B (microtubule‐associated protein 1A/1B‐light chain 3). Western blots show that LC3B expression increased in HEK/293 cells overexpressing MK‐STYX. This correlation elaborates upon previous research, having potential for developing a deeper understanding of the mechanisms with which MK‐STYX affects the decrease of stress granules in the cell. Our future studies will characterize MK‐STYX’ relationship to other autophagic proteins. Further elucidating the interactions and mechanisms of and between MK‐STYX and autophagic proteins may aid in unfolding the ways in which MK‐STYX halts the assembly of stress granules.