Name: phosphorylation and protein control
Uploaded: 2019-03-11T09:21:10.000Z
Duration: 1 min 2 s
Channel: JoVE

K12 Standards

Virginia  Standards of Learning

HIgh School

Life Science

LS.4

LS.4.b

Phosphorylation

- [Profesor] La fosforilación,

la adición de un grupo de fosfato,

es una modificación importante
para que las células

regulen la función de las proteínas.

Al quitar un grupo de fosfato
por hidrólisis del ATP,

las enzimas,
llamadas proteínas quinasas,

pueden catalizar el enlace
covalente de este grupo

a ciertos cadenas laterales de
aminoácidos en una proteína.

Como resultado,
la proteína cambia de forma

o permite que otras proteínas

se adhieran
a las regiones fosforiladas.

Estos cambios pueden modificar
la función de una proteína

y hasta pueden activarla
o desactivarla por completo.

El grupo de fosfato puede quitarse

por la acción
de proteínas fosfatasas,

enzimas que catalizan la
desfosforilación de las proteínas,

básicamente revirtiendo la reacción.

Al regular la fosforilación así,

la actividad de ciertas proteínas

puede activarse, desactivarse

o modificarse
según necesite la célula.

Kyriakis, John M. "Al principio, había fosforilación de proteínas". The Journal of Biological Chemistry 289, no. 14 (4 de abril de 2014): 9460–62. [<a href="https://doi.org/10.1074/jbc.R114.557926" target="__blank">Fuente</a>]
Ardito, Fátima, Michele Giuliani, Donatella Perrone, Giuseppe Troiano y Lorenzo Lo Muzio. "El papel crucial de la fosforilación de proteínas en la señalización celular y su uso como terapia dirigida (revisión)". Revista Internacional de Medicina Molecular 40, no. 2 (agosto de 2017): 271–80. [<a href="https://doi.org/10.3892/ijmm.2017.3036" target="__blank">Fuente</a>]

fosforilación

La adición o eliminación de grupos fosfato de las proteínas es la modificación química más común que regula los procesos celulares. Estas modificaciones pueden afectar la estructura, actividad, estabilidad y localización de proteínas dentro de las células, así como sus interacciones con otras proteínas. Durante la fosforilación, las proteínas quinasas transfieren el grupo fosfato terminal del ATP a cadenas laterales de aminoácidos específicas de proteínas sustrato. La serina, la treonina y la tirosina son los aminoácidos fosforilados más comúnmente. En consecuencia, las proteínas quinasas se clasifican como serina/treonina quinasas, tirosina quinasas o quinasas de acción dual si pueden fosforilar los tres aminoácidos. Por el contrario, las proteínas fosfatasas catalizan la eliminación del grupo fosfato (desfosforilación), restaurando las propiedades originales de la proteína. En condiciones fisiológicas, la fosforilación y desfosforilación están estrechamente reguladas para evitar cambios prolongados en la estructura y función de las proteínas. La alteración de este equilibrio puede provocar enfermedades, incluido el cáncer y diversos trastornos neurodegenerativos. Por ejemplo, una proteína llamada tau está hiperfosforilada en la enfermedad de Alzheimer (EA). Fisiológicamente, tau regula la forma, estructura y desarrollo de las neuronas. La proteína tau contiene más de 80 residuos de serina, treonina y tirosina, de los cuales solo una fracción suele estar fosforilada. En el cerebro de pacientes con EA, la tau está anormal y excesivamente fosforilada. Esto altera la solubilidad de la proteína, formando agregados tóxicos insolubles que provocan la muerte neuronal.

Fosforilación

La adición o eliminación de grupos fosfato de las proteínas es la modificación química más común que regula los procesos celulares. Estas modificaciones ...

Education

Educación

JoVE Core

Biology

Biología

Cellular Processes

Procesos celulares

Metabolism

Metabolismo

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

phosphorylation and protein control

Phosphorylation helps control how proteins work in cells. It is the addition or removal of phosphate groups, and it is the most common chemical change that regulates cellular processes. These changes can alter a protein’s structure, activity, stability, location inside the cell, and interactions with other proteins.

During phosphorylation, protein kinases move the terminal phosphate group from ATP to a specific amino acid side chain on a target protein. The amino acids most often phosphorylated are serine, threonine, and tyrosine. Protein kinases are grouped as serine/threonine kinases, tyrosine kinases, or dual action kinases when they can phosphorylate all three.

Protein phosphatases carry out the reverse step. They remove the phosphate group in a process called dephosphorylation, which restores the protein’s original properties. In healthy cells, phosphorylation and dephosphorylation are carefully balanced so protein shape and function do not stay changed for too long.

When this balance is disrupted, disease can result. Examples include cancer and several neurodegenerative disorders. Tau is one important example. In healthy neurons, tau helps regulate neuron shape, structure, and development. Tau has more than 80 serine, threonine, and tyrosine sites, but only some are normally phosphorylated. In Alzheimer’s disease, tau becomes hyperphosphorylated, or abnormally over-phosphorylated. This makes the protein less soluble and leads to toxic insoluble aggregates that contribute to neuronal death.

Phosphorylation and Protein Control

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phosphorylation

Phosphorylation helps control how proteins work in cells. It is the addition or removal of phosphate groups, and it is the most common chemical change that regulates cellular processes. These changes can alter a protein’s structure, activity, stability, location inside the cell, and interactions with other proteins. During phosphorylation, protein kinases move the terminal phosphate group from ATP to a specific amino acid side chain on a target protein. The amino acids most often...

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enzyme kinetics

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key terms and concepts

Learn how kinases add phosphate groups, phosphatases remove them, and why balanced phosphorylation matters for cell function and diseases like Alzheimer’s.

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Phosphorylation and Protein Control

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