8w6b
crystal structure of TAX1BP1 SKICH domain in complex with RB1CC1 coiled-coil domain
Structural highlights
FunctionRBCC1_HUMAN Involved in autophagy (PubMed:21775823). Regulates early events but also late events of autophagosome formation through direct interaction with Atg16L1 (PubMed:23392225). Required for the formation of the autophagosome-like double-membrane structure that surrounds the Salmonella-containing vacuole (SCV) during S.typhimurium infection and subsequent xenophagy (By similarity). Involved in repair of DNA damage caused by ionizing radiation, which subsequently improves cell survival by decreasing apoptosis (By similarity). Inhibits PTK2/FAK1 and PTK2B/PYK2 kinase activity, affecting their downstream signaling pathways (PubMed:10769033, PubMed:12221124). Plays a role as a modulator of TGF-beta-signaling by restricting substrate specificity of RNF111 (By similarity). Functions as a DNA-binding transcription factor (PubMed:12095676). Is a potent regulator of the RB1 pathway through induction of RB1 expression (PubMed:14533007). Plays a crucial role in muscular differentiation (PubMed:12163359). Plays an indispensable role in fetal hematopoiesis and in the regulation of neuronal homeostasis (By similarity).[UniProtKB:Q9ESK9][1] [2] [3] [4] [5] [6] [7] Publication Abstract from PubMedTAX1BP1, a multifunctional autophagy adaptor, plays critical roles in different autophagy processes. As an autophagy receptor, TAX1BP1 can interact with RB1CC1, NAP1, and mammalian ATG8 family proteins to drive selective autophagy for relevant substrates. However, the mechanistic bases underpinning the specific interactions of TAX1BP1 with RB1CC1 and mammalian ATG8 family proteins remain elusive. Here, we find that there are two distinct binding sites between TAX1BP1 and RB1CC1. In addition to the previously reported TAX1BP1 SKICH (skeletal muscle and kidney enriched inositol phosphatase (SKIP) carboxyl homology)/RB1CC1 coiled-coil interaction, the first coiled-coil domain of TAX1BP1 can directly bind to the extreme C-terminal coiled-coil and Claw region of RB1CC1. We determine the crystal structure of the TAX1BP1 SKICH/RB1CC1 coiled-coil complex and unravel the detailed binding mechanism of TAX1BP1 SKICH with RB1CC1. Moreover, we demonstrate that RB1CC1 and NAP1 are competitive in binding to the TAX1BP1 SKICH domain, but the presence of NAP1's FIP200-interacting region (FIR) motif can stabilize the ternary TAX1BP1/NAP1/RB1CC1 complex formation. Finally, we elucidate the molecular mechanism governing the selective interactions of TAX1BP1 with ATG8 family members by solving the structure of GABARAP in complex with the non-canonical LIR (LC3-interacting region) motif of TAX1BP1, which unveils a unique binding mode between LIR and ATG8 family protein. Collectively, our findings provide mechanistic insights into the interactions of TAX1BP1 with RB1CC1 and mammalian ATG8 family proteins and are valuable for further understanding the working mode and function of TAX1BP1 in autophagy. Mechanistic insights into the interactions of TAX1BP1 with RB1CC1 and mammalian ATG8 family proteins.,Zhang M, Wang Y, Gong X, Wang Y, Zhang Y, Tang Y, Zhou X, Liu H, Huang Y, Zhang J, Pan L Proc Natl Acad Sci U S A. 2024 Mar 12;121(11):e2315550121. doi: , 10.1073/pnas.2315550121. Epub 2024 Mar 4. PMID:38437556[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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