3tdu | pdb_00003tdu
N-terminal acetylation acts as an avidity enhancer within an interconnected multiprotein complex: Structure of a human Cul1WHB-Dcn1P-acetylated Ubc12N complex
Structural highlights
Function[DCNL1_HUMAN] Part of an E3 ubiquitin ligase complex for neddylation. Required for neddylation of cullin components of E3 cullin-RING ubiquitin ligase complexes by enhancing the rate of cullins neddylation. Functions to recruit the NEDD8-charged E2 enzyme to the cullin component. Involved in the release of inhibitory effets of CAND1 on cullin-RING ligase E3 complex assembly and activity. Acts also as an oncogene facilitating malignant transformation and carcinogenic progression (By similarity). [UBC12_HUMAN] Accepts the ubiquitin-like protein NEDD8 from the UBA3-NAE1 E1 complex and catalyzes its covalent attachment to other proteins. The specific interaction with the E3 ubiquitin ligase RBX1, but not RBX2, suggests that the RBX1-UBE2M complex neddylates specific target proteins, such as CUL1, CUL2, CUL3 and CUL4. Involved in cell proliferation.[1] [2] [CUL1_HUMAN] Core component of multiple cullin-RING-based SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complexes, which mediate the ubiquitination of proteins involved in cell cycle progression, signal transduction and transcription. In the SCF complex, serves as a rigid scaffold that organizes the SKP1-F-box protein and RBX1 subunits. May contribute to catalysis through positioning of the substrate and the ubiquitin-conjugating enzyme. The E3 ubiquitin-protein ligase activity of the complex is dependent on the neddylation of the cullin subunit and is inhibited by the association of the deneddylated cullin subunit with TIP120A/CAND1. The functional specificity of the SCF complex depends on the F-box protein as substrate recognition component. SCF(BTRC) and SCF(FBXW11) direct ubiquitination of CTNNB1 and participate in Wnt signaling. SCF(FBXW11) directs ubiquitination of phosphorylated NFKBIA. SCF(BTRC) directs ubiquitination of NFKBIB, NFKBIE, ATF4, SMAD3, SMAD4, CDC25A, FBXO5 and probably NFKB2. SCF(SKP2) directs ubiquitination of phosphorylated CDKN1B/p27kip and is involved in regulation of G1/S transition. SCF(SKP2) directs ubiquitination of ORC1, CDT1, RBL2, ELF4, CDKN1A, RAG2, FOXO1A, and probably MYC and TAL1. SCF(FBXW7) directs ubiquitination of cyclin E, NOTCH1 released notch intracellular domain (NICD), and probably PSEN1. SCF(FBXW2) directs ubiquitination of GCM1. SCF(FBXO32) directs ubiquitination of MYOD1. SCF(FBXO7) directs ubiquitination of BIRC2 and DLGAP5. SCF(FBXO33) directs ubiquitination of YBX1. SCF(FBXO11) does not seem to direct ubiquitination of TP53. SCF(BTRC) mediates the ubiquitination of NFKBIA at 'Lys-21' and 'Lys-22'; the degradation frees the associated NFKB1-RELA dimer to translocate into the nucleus and to activate transcription. SCF(Cyclin F) directs ubiquitination of CP110 (By similarity).[3] [4] [5] [6] [7] Publication Abstract from PubMedAlthough most eukaryotic proteins are N-terminally acetylated, structural mechanisms by which N-terminal acetylation mediates protein interactions are largely unknown. Here, we found that N-terminal acetylation of the E2 enzyme, Ubc12, dictates distinctive E3-dependent ligation of the ubiquitin-like protein, Nedd8, to Cul1. Structural, biochemical, biophysical, and genetic analyses revealed how complete burial of Ubc12's N-acetyl-methionine in a hydrophobic pocket in the E3, Dcn1, promotes cullin neddylation. The results suggest that the N-terminal acetyl both directs Ubc12's interactions with Dcn1, and prevents repulsion of a charged N-terminus. Our data provide a link between acetylation and ubiquitin-like protein conjugation, and define a mechanism for N-terminal acetylation-dependent recognition. N-Terminal Acetylation Acts as an Avidity Enhancer Within an Interconnected Multiprotein Complex.,Scott DC, Monda JK, Bennett EJ, Harper JW, Schulman BA Science. 2011 Sep 22. PMID:21940857[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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