5ctr
Crystal structure of human SART3 HAT-C domain-human USP4 DUSP-UBL domain complex
Structural highlights
Disease[SART3_HUMAN] Defects in SART3 are the cause of disseminated superficial actinic porokeratosis type 1 (DSAP1) [MIM:175900]. DSAP1 is an autosomal dominant disorder, characterized by multiple superficial keratotic lesions surrounded by a slightly raised keratotic border, developing during the third or fourth decade of life on sun-exposed areas of skin.[1] Function[SART3_HUMAN] Regulates Tat transactivation activity through direct interaction. May be a cellular factor for HIV-1 gene expression and viral replication.[2] [UBP4_HUMAN] Hydrolase that deubiquitinates target proteins such as the receptor ADORA2A, PDPK1 and TRIM21. Deubiquitination of ADORA2A increases the amount of functional receptor at the cell surface. Plays a role in the regulation of quality control in the ER.[3] [4] [5] [6] Publication Abstract from PubMedSquamous cell carcinoma antigen recognized by T-cells 3 (SART3) is a U4/U6 recycling factor as well as a targeting factor of USP4 and USP15. However, the details of how SART3 recognizes these deubiquitinases and how they get subsequently translocated into the nucleus are not known. Here, we present the crystal structures of the SART3 half-a-tetratricopeptide (HAT) repeat domain alone and in complex with the domain present in ubiquitin-specific protease (DUSP)-ubiquitin-like (UBL) domains of ubiquitin specific protease 4 (USP4). The 12 HAT repeats of SART3 are in two sub-domains (HAT-N and HAT-C) forming a dimer through HAT-C. USP4 binds SART3 at the opposite surface of the HAT-C dimer interface utilizing the beta-structured linker between the DUSP and the UBL domains. The binding affinities of USP4 and USP15 to SART3 are 0.9 muM and 0.2 muM, respectively. The complex structure of SART3 nuclear localization signal (NLS) and importin-alpha reveals bipartite binding, and removal of SART3 NLS prevents the entry of USP4 (and USP15) into the nucleus and abrogates the subsequent deubiquitinase activity of USP4. Structural basis for recruiting and shuttling of the spliceosomal deubiquitinase USP4 by SART3.,Park JK, Das T, Song EJ, Kim EE Nucleic Acids Res. 2016 Apr 7. pii: gkw218. PMID:27060135[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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