5b6c
From Proteopedia
Structural Details of Ufd1 binding to p97
Structural highlights
Disease[TERA_HUMAN] Defects in VCP are the cause of inclusion body myopathy with early-onset Paget disease and frontotemporal dementia (IBMPFD) [MIM:167320]; also known as muscular dystrophy, limb-girdle, with Paget disease of bone or pagetoid amyotrophic lateral sclerosis or pagetoid neuroskeletal syndrome or lower motor neuron degeneration with Paget-like bone disease. IBMPFD features adult-onset proximal and distal muscle weakness (clinically resembling limb girdle muscular dystrophy), early-onset Paget disease of bone in most cases and premature frontotemporal dementia.[1] [2] [3] [4] [5] Defects in VCP are the cause of amyotrophic lateral sclerosis type 14 with or without frontotemporal dementia (ALS14) [MIM:613954]. ALS14 is a neurodegenerative disorder affecting upper motor neurons in the brain and lower motor neurons in the brain stem and spinal cord, resulting in fatal paralysis. Sensory abnormalities are absent. The pathologic hallmarks of the disease include pallor of the corticospinal tract due to loss of motor neurons, presence of ubiquitin-positive inclusions within surviving motor neurons, and deposition of pathologic aggregates. The etiology of amyotrophic lateral sclerosis is likely to be multifactorial, involving both genetic and environmental factors. The disease is inherited in 5-10% of the cases. Patients with ALS14 may develop frontotemporal dementia.[6] Function[TERA_HUMAN] Necessary for the fragmentation of Golgi stacks during mitosis and for their reassembly after mitosis. Involved in the formation of the transitional endoplasmic reticulum (tER). The transfer of membranes from the endoplasmic reticulum to the Golgi apparatus occurs via 50-70 nm transition vesicles which derive from part-rough, part-smooth transitional elements of the endoplasmic reticulum (tER). Vesicle budding from the tER is an ATP-dependent process. The ternary complex containing UFD1L, VCP and NPLOC4 binds ubiquitinated proteins and is necessary for the export of misfolded proteins from the ER to the cytoplasm, where they are degraded by the proteasome. The NPLOC4-UFD1L-VCP complex regulates spindle disassembly at the end of mitosis and is necessary for the formation of a closed nuclear envelope. Regulates E3 ubiquitin-protein ligase activity of RNF19A (By similarity). Component of the VCP/p97-AMFR/gp78 complex that participates in the final step of the sterol-mediated ubiquitination and endoplasmic reticulum-associated degradation (ERAD) of HMGCR. Also involved in DNA damage response: recruited to double-strand breaks (DSBs) sites in a RNF8- and RNF168-dependent manner and promotes the recruitment of TP53BP1 at DNA damage sites. Recruited to stalled replication forks by SPRTN: may act by mediating extraction of DNA polymerase eta (POLH) to prevent excessive translesion DNA synthesis and limit the incidence of mutations induced by DNA damage.[7] [8] [9] [10] [11] [12] [13] Publication Abstract from PubMedThe hexameric ATPase p97 has been implicated in diverse cellular processes through interactions with many different adaptor proteins at its N-terminal domain. Among these, the Ufd1-Npl4 heterodimer is a major adaptor, and the p97-Ufd1-Npl4 complex plays an essential role in endoplasmic reticulum-associated degradation (ERAD), acting as a segregase that translocates the ubiquitinated client protein from the ER membrane into the cytosol for proteasomal degradation. We determined the crystal structure of the complex of the N-terminal domain of p97 and the SHP box of Ufd1 at a resolution of 1.55 A. The 11-residue-long SHP box of Ufd1 binds at the far-most side of the Nc lobe of the p97 N domain primarily through hydrophobic interactions, such that F225, F228, N233 and L235 of the SHP box contact hydrophobic residues on the surface of the p97 Nc lobe. Mutating these key interface residues abolished the interactions in two different binding experiments, isothermal titration calorimetry and co-immunoprecipitation. Furthermore, cycloheximide chase assays showed that these same mutations caused accumulation of tyrosinase-C89R, a well-known ERAD substrate, thus implying decreased rate of protein degradation due to their defects in ERAD function. Together, these results provide structural and biochemical insights into the interaction between p97 N domain and Ufd1 SHP box. Structural Details of Ufd1 Binding to p97 and Their Functional Implications in ER-Associated Degradation.,Le LT, Kang W, Kim JY, Le OT, Lee SY, Yang JK PLoS One. 2016 Sep 29;11(9):e0163394. doi: 10.1371/journal.pone.0163394., eCollection 2016. PMID:27684549[14] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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