Yang Xu

All Publications

• Active conformation of the p97-p47 unfoldase complex. Nature communications Xu, Y., Han, H., Cooney, I., Guo, Y., Moran, N. G., Zuniga, N. R., Price, J. C., Hill, C. P., Shen, P. S. 2022; 13 (1): 2640

  Abstract

  The p97 AAA+ATPase is an essential and abundant regulator of protein homeostasis that plays a central role in unfolding ubiquitylated substrates. Here we report two cryo-EM structures of human p97 in complex with its p47 adaptor. One of the conformations is six-fold symmetric, corresponds to previously reported structures of p97, and lacks bound substrate. The other structure adopts a helical conformation, displays substrate running in an extended conformation through the pore of the p97 hexamer, and resembles structures reported for other AAA unfoldases. These findings support the model that p97 utilizes a "hand-over-hand" mechanism in which two residues of the substrate are translocated for hydrolysis of two ATPs, one in each of the two p97 AAA ATPase rings. Proteomics analysis supports the model that one p97 complex can bind multiple substrate adaptors or binding partners, and can process substrates with multiple types of ubiquitin modification.

  View details for DOI 10.1038/s41467-022-30318-3

  View details for PubMedID 35552390

  View details for PubMedCentralID PMC9098461

• YWHA/14-3-3 proteins recognize phosphorylated TFEB by a noncanonical mode for controlling TFEB cytoplasmic localization. Autophagy Xu, Y., Ren, J., He, X., Chen, H., Wei, T., Feng, W. 2019; 15 (6): 1017-1030

  Abstract

  As a master regulator of the macroautophagy/autophagy-lysosomal pathway, TFEB (transcription factor EB) plays a prominent role in regulating neurodegenerative diseases and cancer. The transcription activity of TFEB is tightly controlled by phosphorylation and dephosphorylation. Phosphorylated S211 (p-S211) of TFEB can be recognized by YWHA/14-3-3 proteins for TFEB cytoplasmic localization. Here, we characterized the interactions between phosphorylated TFEB and YWHA/14-3-3 proteins and determined the structures of YWHA/14-3-3 proteins in complex with a TFEB p-S211-peptide. Although the critical arginine for YWHA/14-3-3 recognition is missing in the N terminus of the TFEB p-S211-peptide, the C-terminal additional hydrophobic residues of the peptide unexpectedly occupy nearly half of the target-binding groove of YWHA/14-3-3 proteins, which compensates for the N-terminal defect and is distinct from the canonical YWHA/14-3-3-binding mode. Mutations of essential residues in the interaction interface between TFEB and YWHA/14-3-3 proteins disrupted their interactions and severely impaired the cytoplasmic localization of TFEB, which altered the expression of TFEB target genes and affected autophagy. Thus, YWHA/14-3-3 proteins recognize phosphorylated TFEB by a noncanonical mode for controlling TFEB cytoplasmic localization and its activity. Abbreviation: ACTB: actin beta; ALP: autophagy-lysosomal pathway; ATP6V1H: ATPase H+ transporting V1 subunit H; bHLH: basic helix-loop-helix; CLEAR: coordinated lysosomal expression and regulation; Co-IP: co-immunoprecipitation; CTSB: cathepsin B; CTSD: cathepsin D; LAMP1: lysosomal associated membrane protein 1; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MITF: melanocyte inducing transcription factor; NLS: nuclear localization signal; TFEB: transcription factor EB; YWHA/14-3-3: tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein.

  View details for DOI 10.1080/15548627.2019.1569928

  View details for PubMedID 30653408

  View details for PubMedCentralID PMC6526839

• Structural conservation of the autoinhibitory domain in SUN proteins. Biochemical and biophysical research communications Xu, Y., Li, W., Ke, H., Feng, W. 2018; 496 (4): 1337-1343

  Abstract

  LINC complexes span across the nuclear envelope and are assembled by SUN and KASH proteins. SUN1 and SUN2 are the two most abundant SUN proteins in mammals. In SUN2, the predicted coiled-coil domain preceding the SUN domain forms a three-helix bundle that constitutes an autoinhibitory domain (AID) to lock down the SUN domain. Here, we found that SUN1 also contains an AID preceding the SUN domain and solved the structure of the AID-SUN tandem of SUN1. SUN1 AID also adopts a three-helix bundle conformation that interacts with the SUN domain and keeps it in an autoinhibited state. Disruptions of the interaction interface in the AID-SUN tandem restored the SUN domain activity for binding to the KASH peptide. Structural comparison further demonstrated that the autoinhibited conformations of the AID-SUN tandems from SUN1 and SUN2 are similar and the intramolecular interdomain packing in SUN1 is slightly more compact than that in SUN2 due to minor variations of the residues in the interaction interface. Thus, AID is a conserved functional domain in SUN proteins and this work provides the structural evidence to support the conversation of the AID-mediated autoinhibition of SUN proteins.

  View details for DOI 10.1016/j.bbrc.2018.02.015

  View details for PubMedID 29408528