5xmc
From Proteopedia
Crystal structure of the auto-inhibited Nedd4 family E3 ligase Itch
Structural highlights
Disease[ITCH_MOUSE] Note=Defects in Itch are the cause of the itchy phenotype which is an inflammatory and immunological condition characterized by inflammation in the lung and stomach, hyperplasia in lymphoid and hematopoietic cells and constant itching in the skin.[1] Function[ITCH_MOUSE] Acts as an E3 ubiquitin-protein ligase which accepts ubiquitin from an E2 ubiquitin-conjugating enzyme in the form of a thioester and then directly transfers the ubiquitin to targeted substrates. It catalyzes 'Lys-29'-, 'Lys-48'- and 'Lys-63'-linked ubiquitin conjugation. It is involved in the control of inflammatory signaling pathways. Is an essential component of a ubiquitin-editing protein complex, comprising also TNFAIP3, TAX1BP1 and RNF11, that ensures the transient nature of inflammatory signaling pathways. Promotes the association of the complex after TNF stimulation. Once the complex is formed, TNFAIP3 deubiquitinates 'Lys-63' polyubiquitin chains on RIPK1 and catalyzes the formation of 'Lys-48'-polyubiquitin chains. This leads to RIPK1 proteasomal degradation and consequently termination of the TNF- or LPS-mediated activation of NFKB1 (By similarity). Ubiquitinates RIPK2 by 'Lys-63'-linked conjugation and influences NOD2-dependent signal transduction pathways (By similarity). Regulates the transcriptional activity of several transcription factors involved in immune response. Critical regulator of T-helper (TH2) cytokine development through its ability to induce JUNB ubiquitination and degradation. Ubiquitinates SNX9 (By similarity). Ubiquitinates CXCR4 and HGS/HRS and regulates sorting of CXCR4 to the degradative pathway (By similarity). It is involved in the negative regulation of MAVS-dependent cellular antiviral responses. Ubiquitinates MAVS through 'Lys-48'-linked conjugation resulting in MAVS proteasomal degradation (By similarity). Involved in the regulation of apoptosis and reactive oxygen species levels through the ubiquitination and proteasomal degradation of TXNIP (By similarity). Mediates the antiapoptotic activity of epidermal growth factor through the ubiquitination and proteasomal degradation of p15 BID. Targets DTX1 for lysosomal degradation and controls NOTCH1 degradation, in the absence of ligand, through 'Lys-29'-linked polyubiquitination (By similarity).[2] [3] [4] [5] [6] Publication Abstract from PubMedThe Nedd4 family E3 ligases are key regulators of cell growth and proliferation and are often misregulated in human cancers and other diseases. The ligase activities of Nedd4 E3s are tightly controlled via auto-inhibition. However, the molecular mechanism underlying Nedd4 E3 auto-inhibition and activation is poorly understood. Here, we show that the WW domains proceeding the catalytic HECT domain play an inhibitory role by binding directly to HECT in the Nedd4 E3 family member Itch. Our structural and biochemical analyses of Itch reveal that the WW2 domain and a following linker allosterically lock HECT in an inactive state inhibiting E2-E3 transthiolation. Binding of the Ndfip1 adaptor or JNK1-mediated phosphorylation relieves the auto-inhibition of Itch in a WW2-dependent manner. Aberrant activation of Itch leads to migration defects of cortical neurons during development. Our study provides a new mechanism governing the regulation of Itch. Allosteric auto-inhibition and activation of the Nedd4 family E3 ligase Itch.,Zhu K, Shan Z, Chen X, Cai Y, Cui L, Yao W, Wang Z, Shi P, Tian C, Lou J, Xie Y, Wen W EMBO Rep. 2017 Sep;18(9):1618-1630. doi: 10.15252/embr.201744454. Epub 2017 Jul, 26. PMID:28747490[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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