Structural highlights
Function
[VSR1_ARATH] Vacuolar-sorting receptor (VSR) involved in clathrin-coated vesicles sorting from Golgi apparatus to vacuoles. Required for the sorting of 12S globulin, 2S albumin and maybe other seed storage proteins to protein storage vacuoles (PSVs) in seeds. May also be implicated in targeting N-terminal propeptide containing proteins to lytic vacuoles.[1] [2]
Publication Abstract from PubMed
In plant cells, soluble proteins are directed to vacuoles because they contain vacuolar sorting determinants (VSDs) that are recognized by vacuolar sorting receptors (VSR). To understand how a VSR recognizes its cargo, we present the crystal structures of the protease-associated domain of VSR isoform 1 from Arabidopsis thaliana (VSR1PA) alone and complexed with a cognate peptide containing the barley (Hordeum vulgare) aleurain VSD sequence of 1ADSNPIRPVT10. The crystal structures show that VSR1PA binds the sequence, Ala-Asp-Ser, preceding the NPIR motif. A conserved cargo binding loop, with a consensus sequence of 95RGxCxF100, forms a cradle that accommodates the cargo-peptide. In particular, Arg-95 forms a hydrogen bond to the Ser-3 position of the VSD, and the essential role of Arg-95 and Ser-3 in receptor-cargo interaction was supported by a mutagenesis study. Cargo binding induces conformational changes that are propagated from the cargo binding loop to the C terminus via conserved residues in switch I-IV regions. The resulting 180 degrees swivel motion of the C-terminal tail is stabilized by a hydrogen bond between Glu-24 and His-181. A mutagenesis study showed that these two residues are essential for cargo interaction and trafficking. Based on our structural and functional studies, we present a model of how VSRs recognize their cargos.
How vacuolar sorting receptor proteins interact with their cargo proteins: crystal structures of apo and cargo-bound forms of the protease-associated domain from an Arabidopsis vacuolar sorting receptor.,Luo F, Fong YH, Zeng Y, Shen J, Jiang L, Wong KB Plant Cell. 2014 Sep;26(9):3693-708. doi: 10.1105/tpc.114.129940. Epub 2014 Sep, 30. PMID:25271241[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Ahmed SU, Rojo E, Kovaleva V, Venkataraman S, Dombrowski JE, Matsuoka K, Raikhel NV. The plant vacuolar sorting receptor AtELP is involved in transport of NH(2)-terminal propeptide-containing vacuolar proteins in Arabidopsis thaliana. J Cell Biol. 2000 Jun 26;149(7):1335-44. PMID:10871276
- ↑ Shimada T, Fuji K, Tamura K, Kondo M, Nishimura M, Hara-Nishimura I. Vacuolar sorting receptor for seed storage proteins in Arabidopsis thaliana. Proc Natl Acad Sci U S A. 2003 Dec 23;100(26):16095-100. Epub 2003 Dec 4. PMID:14657332 doi:http://dx.doi.org/10.1073/pnas.2530568100
- ↑ Luo F, Fong YH, Zeng Y, Shen J, Jiang L, Wong KB. How vacuolar sorting receptor proteins interact with their cargo proteins: crystal structures of apo and cargo-bound forms of the protease-associated domain from an Arabidopsis vacuolar sorting receptor. Plant Cell. 2014 Sep;26(9):3693-708. doi: 10.1105/tpc.114.129940. Epub 2014 Sep, 30. PMID:25271241 doi:http://dx.doi.org/10.1105/tpc.114.129940
