8yfn
Crystal structure of FIP200 claw in complex with TNIP1_FIR_pS123 peptide with an elongated C terminus
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 PubMedTNIP1 has been increasingly recognized as a security check to finely adjust the rate of mitophagy by disrupting the recycling of the Unc-51-like kinase (ULK) complex during autophagosome formation. Through tank-binding kinase 1 (TBK1)-mediated phosphorylation of the TNIP1 FIR motif, the binding affinity of TNIP1 for FIP200, a component of the ULK complex, is enhanced, allowing TNIP1 to outcompete autophagy receptors. Consequently, FIP200 is released from the autophagosome, facilitating further autophagosome expansion. However, the molecular basis by which FIP200 utilizes its claw domain to distinguish the phosphorylation status of residues in the TNIP1 FIP200 interacting region (FIR) motif for recognition is not well understood. Here, we elucidated multiple crystal structures of the complex formed by the FIP200 claw domain and various phosphorylated TNIP1 FIR peptides. Structural and isothermal titration calorimetry (ITC) analyses identified the crucial residues in the FIP200 claw domain responsible for the specific recognition of phosphorylated TNIP1 FIR peptides. Additionally, utilizing structural comparison and molecular dynamics (MD) simulation data, we demonstrated that the C-terminal tail of TNIP1 peptide affected its binding to the FIP200 claw domain. Moreover, the phosphorylation of TNIP1 Ser123 enabled the peptide to effectively compete with the peptide p-CCPG1 (the FIR motif of the autophagy receptor CCPG1) for binding with the FIP200 claw domain. Overall, our work provides a comprehensive understanding of the specific recognition of phosphorylated TNIP1 by the FIP200 claw domain, marking an initial step toward fully understanding the molecular mechanism underlying the TNIP1-dependent inhibition of mitophagy. Structural basis for TNIP1 binding to FIP200 during mitophagy.,Wu S, Li M, Wang L, Yang L, Cui J, Li F, Wang Q, Shi Y, Lv M J Biol Chem. 2024 Jul 24:107605. doi: 10.1016/j.jbc.2024.107605. PMID:39059492[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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