An allosteric switch between the activation loop and a c-terminal palindromic phosphomotif controls c-Src function.
Autor: Cuesta-Hernández, Hipólito Nicolás; Contreras, Julia; Soriano Maldonado, Pablo; Sánchez Wandelmer, Jana; Yeung, Wayland; Martín-Hurtado, Ana; Muñoz, Inés G.; Kannan, Natarajan; Llimargas, Marta; Muñoz, Javier; Plaza-Menacho, Iván
Resumen: Autophosphorylation controls the transition between discrete functional and
conformational states in protein kinases, yet the structural and molecular
determinants underlying this fundamental process remain unclear. Here we
show that c-terminal Tyr 530 is a de facto c-Src autophosphorylation site with
slow time-resolution kinetics and a strong intermolecular component. On the
contrary, activation-loop Tyr 419 undergoes faster kinetics and a cis-to-trans
phosphorylation switch that controls c-terminal Tyr 530 autophosphorylation,
enzyme specificity, and strikingly, c-Src non-catalytic function as a substrate.
In line with this, we visualize by X-ray crystallography a snapshot of Tyr 530
intermolecular autophosphorylation. In an asymmetric arrangement of both
catalytic domains, a c-terminal palindromic phospho-motif flanking Tyr 530 on
the substrate molecule engages the G-loop of the active kinase adopting a
position ready for entry into the catalytic cleft. Perturbation of the phosphomotif
accounts for c-Src dysfunction as indicated by viral and colorectal cancer
(CRC)-associated c-terminal deleted variants.Weshow that c-terminal residues
531 to 536 are required for c-Src Tyr 530 autophosphorylation, and such a
detrimental effect is caused by the substrate molecule inhibiting allosterically
the active kinase. Our work reveals a crosstalk between the activation and
c-terminal segments that control the allosteric interplay between substrateand
enzyme-acting kinases during autophosphorylation.
Identificador universal: https://hdl.handle.net/10641/3593
Fecha: 2023
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