. "FUNCTION: 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. Ubiquitinates RIPK2 by 'Lys-63'-linked conjugation and influences NOD2-dependent signal transduction pathways. Regulates the transcriptional activity of several transcription factors, and probably plays an important role in the regulation of immune response. Ubiquitinates NFE2 by 'Lys-63' linkages and is implicated in the control of the development of hematopoietic lineages. Critical regulator of T-helper (TH2) cytokine development through its ability to induce JUNB ubiquitination and degradation (By similarity). Ubiquitinates SNX9. Ubiquitinates CXCR4 and HGS/HRS and regulates sorting of CXCR4 to the degradative pathway. 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. Involved in the regulation of apoptosis and reactive oxygen species levels through the ubiquitination and proteasomal degradation of TXNIP. 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. ENZYME REGULATION: Activated by NDFIP1- and NDFIP2-binding (By similarity). PATHWAY: Protein modification; protein ubiquitination. SUBUNIT: Monomer (By similarity) Interacts (via its WW domains) with OCNL, NOTCH1 AND JUN. Interacts (via WW domain 2) with N4BP1; leading to inhibits its E3 ubiquitin-protein ligase activity. Interacts with JUNB; the interaction promotes ITCH-mediated ubiquitination and degradation of JUNB. Interacts with NDFIP1 and NDFIP2; this interaction activates the E3 ubiquitin-protein ligase and may induce its recruitment to exosomes (By similarity). Interacts with ARHGEF7. Interacts with RNF11. Interacts (via the WW 1 domain) with NFE2 (via the PXY motif 1); the interaction promotes 'Lys-63'-linked ubiquitination of NFE2, retains it in the cytoplasm and prevents its transactivation activity. Interacts with FYN; the interaction phosphorylates ITCH on Tyr-420 decreasing binding of JUNB. Interacts (via WW domains) with CXCR4 (via C-terminus); the interaction depends on CXCR4 phosphorylation. Interacts (via WW domains) with PCBP2 within a complex containing ITCH, MAVS and PCBP2. Interacts (via WW domains) with TXNIP (via C-terminus). Interacts with p15 BID. Interacts with ERBB4, DTX1, SPG20, SNX9 and SNX18. Interacts (via its WW domains) with ATN1. Interacts with Epstein-Barr virus LMP2A. Interacts (via WW domains) with SGK3. SUBCELLULAR LOCATION: Cell membrane. Cytoplasm (By similarity). Nucleus. Note=Associates with endocytic vesicles. May be recruited to exosomes by NDFIP1. ALTERNATIVE PRODUCTS: Event=Alternative splicing; Named isoforms=2; Name=1; IsoId=Q96J02-1; Sequence=Displayed; Note=No experimental confirmation available; Name=2; IsoId=Q96J02-2; Sequence=VSP_008451; TISSUE SPECIFICITY: Widely expressed. PTM: On T-cell activation, phosphorylation by the JNK cascade on serine and threonine residues surrounding the PRR domain accelerates the ubiquitination and degradation of JUN and JUNB. The increased ITCH catalytic activity due to phosphorylation by JNK1 may occur due to a conformational change disrupting the interaction between the PRR/WW motifs domain and the HECT domain and, thus exposing the HECT domain (By similarity). Phosphorylation by FYN reduces interaction with JUNB and negatively controls JUN ubiquitination and degradation. PTM: Ubiquitinated; autopolyubiquitination with 'Lys-63' linkages which does not lead to protein degradation. DISEASE: Defects in ITCH are the cause of syndromic multisystem autoimmune disease (SMAD) [MIM:613385]. SMAD is characterized by organomegaly, failure to thrive, developmental delay, dysmorphic features and autoimmune inflammatory cell infiltration of the lungs, liver and gut. SIMILARITY: Contains 1 C2 domain. SIMILARITY: Contains 1 HECT (E6AP-type E3 ubiquitin-protein ligase) domain. SIMILARITY: Contains 4 WW domains. GENE SYNONYMS:ITCH. COPYRIGHT: Protein annotation is derived from the UniProt Consortium (http://www.uniprot.org/). Distributed under the Creative Commons Attribution-NoDerivs License."^^ . "SEQUENCE 903 AA; 102803 MW; 6777A2043C7B67BC CRC64;"^^ . . . . . . . . . . . . . . . "ITCH_HUMAN"^^ . "6.3.2.-"^^ . "NAPP1"^^ . "Itch"^^ . "AIP4"^^ . "ITCH"^^ . "NFE2-associated polypeptide 1"^^ . "Atrophin-1-interacting protein 4"^^ . . . . . . . . "MSDSGSQLGSMGSLTMKSQLQITVISAKLKENKKNWFGPSPYVEVTVDGQSKKTEKCNNTNSPKWKQPLTVIVTPVSKLHFRVWSHQTLKSDVLLGTAALDIYETLKSNNMKLEEVVVTLQLGGDKEPTETIGDLSICLDGLQLESEVVTNGETTCSENGVSLCLPRLECNSAISAHCNLCLPGLSDSPISASRVAGFTGASQNDDGSRSKDETRVSTNGSDDPEDAGAGENRRVSGNNSPSLSNGGFKPSRPPRPSRPPPPTPRRPASVNGSPSATSESDGSSTGSLPPTNTNTNTSEGATSGLIIPLTISGGSGPRPLNPVTQAPLPPGWEQRVDQHGRVYYVDHVEKRTTWDRPEPLPPGWERRVDNMGRIYYVDHFTRTTTWQRPTLESVRNYEQWQLQRSQLQGAMQQFNQRFIYGNQDLFATSQSKEFDPLGPLPPGWEKRTDSNGRVYFVNHNTRITQWEDPRSQGQLNEKPLPEGWEMRFTVDGIPYFVDHNRRTTTYIDPRTGKSALDNGPQIAYVRDFKAKVQYFRFWCQQLAMPQHIKITVTRKTLFEDSFQQIMSFSPQDLRRRLWVIFPGEEGLDYGGVAREWFFLLSHEVLNPMYCLFEYAGKDNYCLQINPASYINPDHLKYFRFIGRFIAMALFHGKFIDTGFSLPFYKRILNKPVGLKDLESIDPEFYNSLIWVKENNIEECDLEMYFSVDKEILGEIKSHDLKPNGGNILVTEENKEEYIRMVAEWRLSRGVEEQTQAFFEGFNEILPQQYLQYFDAKELEVLLCGMQEIDLNDWQRHAIYRHYARTSKQIMWFWQFVKEIDNEKRMRLLQFVTGTCRLPVGGFADLMGSNGPQKFCIEKVGKENWLPRSHTCFNRLDLPPYKSYEQLKEKLLFAIEETEGFGQE"^^ . "E3 ubiquitin-protein ligase Itchy homolog"^^ .