Catalytically inactive phosphatase (PubMed:23847209). Acts as a nuclear anchor for MAPK1/MAPK3 (ERK1/ERK2) (PubMed:23847209). Modulates cell-fate decisions and cell migration by spatiotemporal regulation of MAPK1/MAPK3 (ERK1/ERK2) (PubMed:23847209). By binding to the F-box of FBXW7, prevents the assembly of FBXW7 into the SCF E3 ubiquitin-protein ligase complex, and thereby inhibits degradation of its substrates (PubMed:28007894). Plays a role in spermatogenesis (By similarity).
