7kfl
Crystal structure of the cargo-binding domain from the plant class XI myosin (MyoXIk)Crystal structure of the cargo-binding domain from the plant class XI myosin (MyoXIk)
Structural highlights
FunctionMYO17_ARATH Myosin heavy chain that is required for the cell cycle-regulated transport of various organelles and proteins for their segregation. Functions by binding with its tail domain to receptor proteins on organelles and exerting force with its N-terminal motor domain against actin filaments, thereby transporting its cargo along polarized actin cables. Involved in the tip growth of root hair cells and in the elongation of trichome stalk and branches. Plays a major role in trafficking of Golgi stacks, mitochondria and peroxisomes during root hair development. Acts as the primary contributor to ER streaming with a major role in the movement of Golgi bodies. Required for development of pavement cells, trichomes, and stigmatic papillae.[1] [2] [3] [4] [5] [6] [7] [8] [9] Publication Abstract from PubMedThe plant-specific class XI myosins (MyoXIs) play key roles at the molecular, cellular and tissue levels, engaging diverse adaptor proteins to transport cargoes along actin filaments. To recognize their cargoes, MyoXIs have a C-terminal globular tail domain (GTD) that is evolutionarily related to those of class V myosins (MyoVs) from animals and fungi. Despite recent advances in understanding the functional roles played by MyoXI in plants, the structure of its GTD, and therefore the molecular determinants for cargo selectivity and recognition, remain elusive. In this study, the first crystal structure of a MyoXI GTD, that of MyoXI-K from Arabidopsis thaliana, was elucidated at 2.35 A resolution using a low-identity and fragment-based phasing approach in ARCIMBOLDO_SHREDDER. The results reveal that both the composition and the length of the alpha5-alpha6 loop are distinctive features of MyoXI-K, providing evidence for a structural stabilizing role for this loop, which is otherwise carried out by a molecular zipper in MyoV GTDs. The crystal structure also shows that most of the characterized cargo-binding sites in MyoVs are not conserved in plant MyoXIs, pointing to plant-specific cargo-recognition mechanisms. Notably, the main elements involved in the self-regulation mechanism of MyoVs are conserved in plant MyoXIs, indicating this to be an ancient ancestral trait. Structure of the class XI myosin globular tail reveals evolutionary hallmarks for cargo recognition in plants.,Turowski VR, Ruiz DM, Nascimento AFZ, Millan C, Sammito MD, Juanhuix J, Cremonesi AS, Uson I, Giuseppe PO, Murakami MT Acta Crystallogr D Struct Biol. 2021 Apr 1;77(Pt 4):522-533. doi:, 10.1107/S2059798321001583. Epub 2021 Mar 30. PMID:33825712[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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