Reconstitution Defines the Roles of P62, NBR1 and TAX1BP1 in Ubiquitin Condensate Formation and Autophagy Initiation

Overview

Journal Nat Commun

Specialty Biology

Date 2021 Sep 2

PMID 34471133

Citations 74

Authors

Eleonora Turco

Adriana Savova

Flora Gere

Luca Ferrari

Julia Romanov

Martina Schuschnig

Sascha Martens

Affiliations

Soon will be listed here.

Abstract

The autophagic degradation of misfolded and ubiquitinated proteins is important for cellular homeostasis. In this process, which is governed by cargo receptors, ubiquitinated proteins are condensed into larger structures and subsequently become targets for the autophagy machinery. Here we employ in vitro reconstitution and cell biology to define the roles of the human cargo receptors p62/SQSTM1, NBR1 and TAX1BP1 in the selective autophagy of ubiquitinated substrates. We show that p62 is the major driver of ubiquitin condensate formation. NBR1 promotes condensate formation by equipping the p62-NBR1 heterooligomeric complex with a high-affinity UBA domain. Additionally, NBR1 recruits TAX1BP1 to the ubiquitin condensates formed by p62. While all three receptors interact with FIP200, TAX1BP1 is the main driver of FIP200 recruitment and thus the autophagic degradation of p62-ubiquitin condensates. In summary, our study defines the roles of all three receptors in the selective autophagy of ubiquitin condensates.

Citing Articles

Important regulatory role of mitophagy in diabetic microvascular complications.

Hu X, Lv J, Zhao Y, Li X, Qi W, Wang X J Transl Med. 2025; 23(1):269.

PMID: 40038741 PMC: 11877814. DOI: 10.1186/s12967-025-06307-7.

Beclin 1 of megakaryocytic lineage cells is locally dispensable for platelet hemostasis but functions distally in bone homeostasis.

Li L, Zhao C, Zhang R, Wei W, Liu B, Dong J Bone Res. 2025; 13(1):32.

PMID: 40032858 PMC: 11876339. DOI: 10.1038/s41413-025-00410-7.

p62/SQSTM1 in cancer: phenomena, mechanisms, and regulation in DNA damage repair.

Yang X, Cao X, Zhu Q Cancer Metastasis Rev. 2025; 44(1):33.

PMID: 39954143 PMC: 11829845. DOI: 10.1007/s10555-025-10250-w.

The LC3-interacting region of NBR1 is a protein interaction hub enabling optimal flux.

North B, Ohnstad A, Ragusa M, Shoemaker C J Cell Biol. 2025; 224(4).

PMID: 39928048 PMC: 11809422. DOI: 10.1083/jcb.202407105.

Manipulating autophagic degradation in human diseases: from mechanisms to interventions.

Zhang Y, Liu X, Klionsky D, Lu B, Zhong Q Life Med. 2025; 1(2):120-148.

PMID: 39871921 PMC: 11749641. DOI: 10.1093/lifemedi/lnac043.

References

Walinda E, Morimoto D, Sugase K, Konuma T, Tochio H, Shirakawa M . Solution structure of the ubiquitin-associated (UBA) domain of human autophagy receptor NBR1 and its interaction with ubiquitin and polyubiquitin. J Biol Chem. 2014; 289(20):13890-902. PMC: 4022861. DOI: 10.1074/jbc.M114.555441. View

Lamark T, Perander M, Outzen H, Kristiansen K, Overvatn A, Michaelsen E . Interaction codes within the family of mammalian Phox and Bem1p domain-containing proteins. J Biol Chem. 2003; 278(36):34568-81. DOI: 10.1074/jbc.M303221200. View

Randow F, MacMicking J, James L . Cellular self-defense: how cell-autonomous immunity protects against pathogens. Science. 2013; 340(6133):701-6. PMC: 3863583. DOI: 10.1126/science.1233028. View

Shi X, Chang C, Yokom A, Jensen L, Hurley J . The autophagy adaptor NDP52 and the FIP200 coiled-coil allosterically activate ULK1 complex membrane recruitment. Elife. 2020; 9. PMC: 7447430. DOI: 10.7554/eLife.59099. View

Ichimura Y, Kumanomidou T, Sou Y, Mizushima T, Ezaki J, Ueno T . Structural basis for sorting mechanism of p62 in selective autophagy. J Biol Chem. 2008; 283(33):22847-57. DOI: 10.1074/jbc.M802182200. View

Ciuffa R, Lamark T, Tarafder A, Guesdon A, Rybina S, Hagen W . The selective autophagy receptor p62 forms a flexible filamentous helical scaffold. Cell Rep. 2015; 11(5):748-58. DOI: 10.1016/j.celrep.2015.03.062. View

Wurzer B, Zaffagnini G, Fracchiolla D, Turco E, Abert C, Romanov J . Oligomerization of p62 allows for selection of ubiquitinated cargo and isolation membrane during selective autophagy. Elife. 2015; 4:e08941. PMC: 4684078. DOI: 10.7554/eLife.08941. View

Kirkin V, Rogov V . A Diversity of Selective Autophagy Receptors Determines the Specificity of the Autophagy Pathway. Mol Cell. 2019; 76(2):268-285. DOI: 10.1016/j.molcel.2019.09.005. View

Schneider C, Rasband W, Eliceiri K . NIH Image to ImageJ: 25 years of image analysis. Nat Methods. 2012; 9(7):671-5. PMC: 5554542. DOI: 10.1038/nmeth.2089. View

10.

Ravenhill B, Boyle K, von Muhlinen N, Ellison C, Masson G, Otten E . The Cargo Receptor NDP52 Initiates Selective Autophagy by Recruiting the ULK Complex to Cytosol-Invading Bacteria. Mol Cell. 2019; 74(2):320-329.e6. PMC: 6477152. DOI: 10.1016/j.molcel.2019.01.041. View

11.

Levine B, Kroemer G . Biological Functions of Autophagy Genes: A Disease Perspective. Cell. 2019; 176(1-2):11-42. PMC: 6347410. DOI: 10.1016/j.cell.2018.09.048. View

12.

Turco E, Fracchiolla D, Martens S . Recruitment and Activation of the ULK1/Atg1 Kinase Complex in Selective Autophagy. J Mol Biol. 2019; 432(1):123-134. PMC: 6971721. DOI: 10.1016/j.jmb.2019.07.027. View

13.

Sun D, Wu R, Zheng J, Li P, Yu L . Polyubiquitin chain-induced p62 phase separation drives autophagic cargo segregation. Cell Res. 2018; 28(4):405-415. PMC: 5939046. DOI: 10.1038/s41422-018-0017-7. View

14.

Kirkin V, Lamark T, Sou Y, Bjorkoy G, Nunn J, Bruun J . A role for NBR1 in autophagosomal degradation of ubiquitinated substrates. Mol Cell. 2009; 33(4):505-16. DOI: 10.1016/j.molcel.2009.01.020. View

15.

Jakobi A, Huber S, Mortensen S, Schultz S, Palara A, Kuhm T . Structural basis of p62/SQSTM1 helical filaments and their role in cellular cargo uptake. Nat Commun. 2020; 11(1):440. PMC: 6978347. DOI: 10.1038/s41467-020-14343-8. View

16.

Johansen T, Lamark T . Selective Autophagy: ATG8 Family Proteins, LIR Motifs and Cargo Receptors. J Mol Biol. 2019; 432(1):80-103. DOI: 10.1016/j.jmb.2019.07.016. View

17.

Isogai S, Morimoto D, Arita K, Unzai S, Tenno T, Hasegawa J . Crystal structure of the ubiquitin-associated (UBA) domain of p62 and its interaction with ubiquitin. J Biol Chem. 2011; 286(36):31864-74. PMC: 3173063. DOI: 10.1074/jbc.M111.259630. View

18.

Mizushima N, Yoshimori T, Ohsumi Y . The role of Atg proteins in autophagosome formation. Annu Rev Cell Dev Biol. 2011; 27:107-32. DOI: 10.1146/annurev-cellbio-092910-154005. View

19.

Ohnstad A, Delgado J, North B, Nasa I, Kettenbach A, Schultz S . Receptor-mediated clustering of FIP200 bypasses the role of LC3 lipidation in autophagy. EMBO J. 2020; 39(24):e104948. PMC: 7737610. DOI: 10.15252/embj.2020104948. View

20.

Mizushima N, Komatsu M . Autophagy: renovation of cells and tissues. Cell. 2011; 147(4):728-41. DOI: 10.1016/j.cell.2011.10.026. View