RESUMO
SignificanceThe pseudokinase integrin-linked kinase (ILK) is a central component of focal adhesions, cytoplasmic multiprotein complexes that integrate and transduce biochemical and mechanical signals from the extracellular environment into the cell and vice versa. However, the precise molecular functions, particularly the mechanosensory properties of ILK and the significance of retained adenosine triphosphate (ATP) binding, are still unclear. Combining molecular-dynamics simulations with cell biology, we establish a role for ATP binding to pseudokinases. We find that ATP promotes the structural stability of ILK, allosterically influences the interaction between ILK and its binding partner parvin at adhesions, and enhances the mechanoresistance of this complex. On the cellular level, ATP binding facilitates efficient traction force buildup, focal adhesion stabilization, and efficient cell migration.
Assuntos
Trifosfato de Adenosina/química , Trifosfato de Adenosina/metabolismo , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/metabolismo , Actomiosina/química , Actomiosina/metabolismo , Regulação Alostérica , Sítios de Ligação , Adesão Celular , Movimento Celular , Estabilidade Enzimática , Adesões Focais , Mecanotransdução Celular , Proteínas dos Microfilamentos/química , Proteínas dos Microfilamentos/metabolismo , Modelos Moleculares , Conformação Molecular , Mutação , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Proteínas Serina-Treonina Quinases/genética , Relação Estrutura-Atividade , Especificidade por SubstratoRESUMO
The inner centromere protein, INCENP, is crucial for correct chromosome segregation during mitosis. It connects the kinase Aurora B to the inner centromere allowing this kinase to dynamically access its kinetochore targets. However, the function of its central, 440-residue long intrinsically disordered region (IDR) and its multiple phosphorylation sites is unclear. Here, we determined the conformational ensemble of INCENP's IDR, systematically varying the level of phosphorylation, using all-atom and coarse-grain molecular dynamics simulations. Our simulations show that phosphorylation expands INCENP's IDR, both locally and globally, mainly by increasing its overall net charge. The disordered region undergoes critical globule-to-coil conformational transitions and the transition temperature non-monotonically depends on the degree of phosphorylation, with a mildly phosphorylated case of neutral net charge featuring the highest collapse propensity. The IDR transitions from a multitude of globular states, accompanied by several specific internal contacts that reduce INCENP length by loop formation, to weakly interacting and highly extended coiled conformations. Phosphorylation critically shifts the population between these two regimes. It thereby influences cohesiveness and phase behavior of INCENP IDR assemblies, a feature presumably relevant for INCENP's function in the chromosomal passenger complex. Overall, we propose the disordered region of INCENP to act as a phosphorylation-regulated and length-variable component, within the previously defined "dog-leash" model, that thereby regulates how Aurora B reaches its targets for proper chromosome segregation.
Assuntos
Proteínas Cromossômicas não Histona/química , Proteínas Cromossômicas não Histona/metabolismo , Proteínas Intrinsicamente Desordenadas/química , Aurora Quinase B/metabolismo , Humanos , Proteínas Intrinsicamente Desordenadas/metabolismo , Simulação de Dinâmica Molecular , Transição de Fase , Fosforilação , Conformação Proteica em alfa-HéliceRESUMO
Esta investigación es una alternativa conceptual a la clásica interpretación de larelación entre cultura y cognición. Con el objetivo de comprobar la influencia del niveleducativo y la experiencia de inmigración en el tipo de discurso empleado, uso deejemplos, voces y contenido del discurso, se analizó un acto propio de la comunicaciónhumana -debate- entre sujetos procedentes de Costa de Marfil y Andalucía. Los resultadosmuestran evidencias de la adecuación del tipo y contenido del discurso, de la presenciade ejemplos y del empleo de diferentes voces en función de las diversas variables culturalesy experiencias vitales(AU)
This research is a conceptual alternative to the classical interpretation of the relationshipbetween culture and cognition. In order to check the influence of the educativelevel and experience of immigration on the type of employee speech, use of examples,voices and content of the speech we analysed an act of human communication -debate-among subjects from Ivory Coast and Andalusia. The results show evidence of theappropriateness of the type and content of the speech, the presence of examples and theuse of different voices depending on several variables cultural and life experiences(AU)
