Structure of the class XI myosin globular tail reveals evolutionary hallmarks for cargo recognition in plants

Author(s)

Turowski, Valeria R. ; Ruiz, Diego M. ; Nascimento, Andrey F. Z. ; Millan, Claudia ; Sammito, Massimo D. ; Juanhuix, Judith ; Cremonesi, Aline Sampaio ; Uson, Isabel ; Giuseppe, Priscila O. ; Murakami, Mario T.

• Document type: Journal article
• Source: ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY; v. 77, p. 12-pg., 2021-04-01.

Abstract

The 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 angstrom 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 alpha 5-alpha 6 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. (AU)

• FAPESP's process: 14/09720-9 - Studies of the role of phosphorylation and protein binding partners in regulating the function of human class V myosins
• Grantee: Mário Tyago Murakami
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/08904-6 - Structural and functional studies of molecular mechanisms involved in the recognition and interaction of myosin XI with cellular cargoes
• Grantee: Valeria Rosana Turowski
• Support Opportunities: Scholarships in Brazil - Post-Doctoral