Conformational flexibility of GRASPs and their constituent PDZ subdomains reveals structural basis of their promiscuous interactome

Autor(es)

Mendes, Luis Felipe S. ^{[1, 2]} ; Batista, Mariana R. B. ^[2] ; Judge, Peter J. ^[1] ; Watts, Anthony ^[1] ; Redfield, Christina ^[1] ; Costa-Filho, Antonio J. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Oxford, Dept Biochem, Oxford - England

^[2] Univ Sao Paulo, Mol Biophys Lab, Ribeirao Preto Sch Philosophy Sci & Literature, Phys Dept, Ribeirao Preto - Brazil

• Tipo de documento: Artigo Científico
• Fonte: FEBS Journal; JAN 2020.
• Citações Web of Science: 0

Resumo

The Golgi complex is a central component of the secretory pathway, responsible for several critical cellular functions in eukaryotes. The complex is organized by the Golgi matrix that includes the Golgi reassembly and stacking protein (GRASP), which was shown to be involved in cisternae stacking and lateral linkage in metazoan. GRASPs also have critical roles in other processes, with an unusual ability to interact with several different binding partners. The conserved N terminus of the GRASP family includes two PSD-95, DLG, and ZO-1 (PDZ) domains. Previous crystallographic studies of orthologues suggest that PDZ1 and PDZ2 have similar conformations and secondary structure content. However, PDZ1 alone mediates nearly all interactions between GRASPs and their partners. In this work, NMR, synchrotron radiation CD, and molecular dynamics (MD) were used to examine the structure, flexibility, and stability of the two constituent PDZ domains. GRASP PDZs are structured in an unusual beta(3)alpha(1)beta(4)beta(5)alpha(2)beta(6)beta(1)beta(2) secondary structural arrangement and NMR data indicate that the PDZ1 binding pocket is formed by a stable beta(2)-strand and a more flexible and unstable alpha(2)-helix, suggesting an explanation for the higher PDZ1 promiscuity. The conformational free energy profiles of the two PDZ domains were calculated using MD simulations. The data suggest that, after binding, the protein partner significantly reduces the conformational space that GRASPs can access by stabilizing one particular conformation, in a partner-dependent fashion. The structural flexibility of PDZ1, modulated by PDZ2, and the coupled, coordinated movement between the two PDZs enable GRASPs to interact with multiple partners, allowing them to function as promiscuous, multitasking proteins. (AU)

• Processo FAPESP: 12/20367-3 - Estudos estruturais e funcionais da proteína de organização e compactação do Golgi (GRASP) de Cryptococcus neoformans
• Beneficiário: Antonio José da Costa Filho
• Linha de fomento: Auxílio à Pesquisa - Regular
• Processo FAPESP: 17/24669-8 - Desvendando as bases moleculares de processos iniciais da secreção de proteínas em humanos utilizando técnicas biofísicas
• Beneficiário: Luis Felipe Santos Mendes
• Linha de fomento: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 16/09676-5 - Estudos de ressonância magnética nuclear da proteína de organização e compactação do Golgi (GRASP) de Cryptococcus neoformans
• Beneficiário: Luis Felipe Santos Mendes
• Linha de fomento: Bolsas no Exterior - Estágio de Pesquisa - Doutorado Direto
• Processo FAPESP: 15/50366-7 - Resolving mechanistic details of peptide transport across membranes using crystallographic and non-crystallographic structural biology approaches
• Beneficiário: Antonio José da Costa Filho
• Linha de fomento: Auxílio à Pesquisa - Regular