| Structural highlights
Function
[GBRL1_HUMAN] Increases cell-surface expression of kappa-type opioid receptor through facilitating anterograde intracellular trafficking of the receptor. Involved in formation of autophagosomal vacuoles.[1] [2] [NBR1_HUMAN] Acts probably as a receptor for selective autophagosomal degradation of ubiquitinated targets.[3]
Publication Abstract from PubMed
Selective autophagy requires the specific segregation of targeted proteins into autophagosomes. The selectivity is mediated by autophagy receptors, such as p62 and NBR1, which can bind to autophagic effector proteins (Atg8 in yeast, MAP1LC3 protein family in mammals) anchored in the membrane of autophagosomes. Recognition of autophagy receptors by autophagy effectors takes place through an LC3 interaction region (LIR). The canonical LIR motif consists of a WXXL sequence, N-terminally preceded by negatively charged residues. The LIR motif of NBR1 presents differences to this classical LIR motif with a tyrosine residue and an isoleucine residue substituting the tryptophan residue and the leucine residue, respectively. We have determined the structure of the GABARAPL-1/NBR1-LIR complex and studied the influence of the different residues belonging to the LIR motif for the interaction with several mammalian autophagy modifiers (LC3B and GABARAPL-1). Our results indicate that the presence of a tryptophan residue in the LIR motif increases the binding affinity. Substitution by other aromatic amino acids or increasing the number of negatively charged residues at the N-terminus of the LIR motif, however, has little effect on the binding affinity due to enthalpy-entropy compensation. This indicates that different LIRs can interact with autophagy modifiers with unique binding properties.
Characterization of the Interaction of GABARAPL-1 with the LIR Motif of NBR1.,Rozenknop A, Rogov VV, Rogova NY, Lohr F, Guntert P, Dikic I, Dotsch V J Mol Biol. 2011 Jul 15;410(3):477-87. Epub 2011 May 18. PMID:21620860[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Chen C, Li JG, Chen Y, Huang P, Wang Y, Liu-Chen LY. GEC1 interacts with the kappa opioid receptor and enhances expression of the receptor. J Biol Chem. 2006 Mar 24;281(12):7983-93. Epub 2006 Jan 23. PMID:16431922 doi:M509805200
- ↑ Chakrama FZ, Seguin-Py S, Le Grand JN, Fraichard A, Delage-Mourroux R, Despouy G, Perez V, Jouvenot M, Boyer-Guittaut M. GABARAPL1 (GEC1) associates with autophagic vesicles. Autophagy. 2010 May;6(4):495-505. doi: 10.4161/auto.6.4.11819. Epub 2010 May 16. PMID:20404487 doi:10.4161/auto.6.4.11819
- ↑ Kirkin V, Lamark T, Sou YS, Bjorkoy G, Nunn JL, Bruun JA, Shvets E, McEwan DG, Clausen TH, Wild P, Bilusic I, Theurillat JP, Overvatn A, Ishii T, Elazar Z, Komatsu M, Dikic I, Johansen T. A role for NBR1 in autophagosomal degradation of ubiquitinated substrates. Mol Cell. 2009 Feb 27;33(4):505-16. doi: 10.1016/j.molcel.2009.01.020. PMID:19250911 doi:10.1016/j.molcel.2009.01.020
- ↑ Rozenknop A, Rogov VV, Rogova NY, Lohr F, Guntert P, Dikic I, Dotsch V. Characterization of the Interaction of GABARAPL-1 with the LIR Motif of NBR1. J Mol Biol. 2011 Jul 15;410(3):477-87. Epub 2011 May 18. PMID:21620860 doi:10.1016/j.jmb.2011.05.003
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