Definition:

Substrate adapter for ufmylation, the covalent attachment of the ubiquitin-like modifier UFM1 to substrate proteins, which plays a key role in reticulophagy (also called ER-phagy). In response to endoplasmic reticulum stress, promotes recruitment of the E3 UFM1-protein ligase UFL1 to the endoplasmic reticulum membrane: in turn, UFL1 mediates ufmylation of proteins such as RPN1 and RPL26/uL24, promoting reticulophagy of endoplasmic reticulum sheets. Ufmylation-dependent reticulophagy inhibits the unfolded protein response (UPR) by regulating ERN1/IRE1-alpha stability. Ufmylation in response to endoplasmic reticulum stress is essential for processes such as hematopoiesis or inflammatory response (By similarity). Required for TRIP4 ufmylation, thereby regulating nuclear receptors-mediated. transcription. May play a role in NF-kappa-B-mediated transcription through regulation of the phosphorylation and the degradation of NFKBIA, the inhibitor of NF-kappa-B. Plays a role in cartilage development through SOX9, inhibiting the ubiquitin-mediated proteasomal degradation of this transcriptional regulator.