FEATURES

DESCRIPTION

Also known as UBQL1_HUMAN, UBQLN1, DA41, PLIC1. Plays an important role in the regulation of different protein degradation mechanisms and pathways including ubiquitin-proteasome system (UPS), autophagy and endoplasmic reticulum-associated protein degradation (ERAD) pathway. Mediates the proteasomal targeting of misfolded or accumulated proteins for degradation by binding (via UBA domain) to their polyubiquitin chains and by interacting (via ubiquitin-like domain) with the subunits of the proteasome (PubMed:15147878). Plays a role in the ERAD pathway via its interaction with ER-localized proteins UBXN4, VCP and HERPUD1 and may form a link between the polyubiquitinated ERAD substrates and the proteasome (PubMed:19822669, PubMed:18307982). Isoform 1, isoform 2 and isoform 3 play a role in unfolded protein response (UPR) by attenuating the induction of UPR-inducible genes, DDTI3/CHOP, HSPA5 and PDIA2 during ER stress (PubMed:18953672). Involved in the regulation of macroautophagy and autophagosome formation; required for maturation of autophagy-related protein LC3 from the cytosolic form LC3-I to the membrane-bound form LC3-II and may assist in the maturation of autophagosomes to autolysosomes by mediating autophagosome-lysosome fusion (PubMed:19148225, PubMed:20529957, PubMed:23459205). Negatively regulates the TICAM1/TRIF-dependent toll-like receptor signaling pathway by decreasing the abundance of TICAM1 via the autophagic pathway (PubMed:21695056). Isoform 1 and isoform 3 play a key role in the regulation of the levels of PSEN1 by targeting its accumulation to aggresomes which may then be removed from cells by autophagocytosis (PubMed:21143716). Promotes the ubiquitination and lysosomal degradation of ORAI1, consequently downregulating the ORAI1-mediated Ca2+ mobilization (PubMed:23307288). Suppresses the maturation and proteasomal degradation of amyloid beta A4 protein (A4) by stimulating the lysine 63 (K63)-linked polyubiquitination. Delays the maturation of A4 by sequestering it in the Golgi apparatus and preventing its transport to the cell surface for subsequent processing (By similarity). Monomer and homodimer. Heterodimer with UBQLN2 (PubMed:16813565). Binds CD47, NBL1, GABRA1, GABRA2, GABRA3, GABRA6, GABRB1, GABRB2 and GABRB3 (By similarity). Binds UBE3A, BTRC, P4HB and MTOR. Interacts with the proteasome 19S subunit. Interacts (via ubiquitin-like domain) with TREX1; the interaction is direct and may control TREX1 subcellular location. Forms a complex with UBXN4 and VCP. Interacts (via UBA domain) with UBQLN4 (via ubiquitin-like domain). Found in a complex with UBQLN2 and MAP1LC3A/B/C. The monomeric form interacts with PSEN2 and the monomeric forms of isoform 1 and isoform 3 interact with PSEN1. Interacts with ORAI1. Interacts (via UBA domain) with TICAM1. Interacts with EPS15. Interacts (via UBA domain) with UBA52 and (via ubiquitin-like domain) with PSMD3 and PSMD4. Interacts with HERPUD1. Interacts with MAP1LC3A/B/C in the presence of UBQLN4. Interacts (via ubiquitin-like domain) with EPS15 (via UIM domains) and both the ubiquitinated and non-ubiquitinated forms can interact with EPS15. Interacts (via ubiquitin-like domain) with EPS15L1, HGS (via UIM domain) and STAM2 (via UIM domain).

EXTERNAL LINKS

UBQLN1

Ubiquilin-1

UBQLN1

Molecular Synopsis