Substrate adapter for ufmylation, the covalent attachment of the ubiquitin-like modifier UFM1 to substrate proteins, in response to endoplasmic reticulum stress (By similarity). Negatively regulates NF-kappa-B-mediated gene transcription through the control of RELA phosphorylation. Probable tumor suppressor initially identified as a CDK5R1 interactor controlling cell proliferation. Also regulates mitotic G2/M transition checkpoint and mitotic G2 DNA damage checkpoint. Through its interaction with CDKN2A/ARF and MDM2 may induce MDM2-dependent p53/TP53 ubiquitination, stabilization and activation in the nucleus, thereby promoting G1 cell cycle arrest and inhibition of cell proliferation. May also play a role in the rupture of the nuclear envelope during apoptosis. May regulate MAPK14 activity by regulating its dephosphorylation by PPM1D/WIP1 (By similarity). Required for liver development (By similarity).
Subcellular locations: Nucleus, Cytoplasm, Cytoplasm, Cytoskeleton, Microtubule organizing center, Centrosome
Colocalizes and associates with microtubules.