Video Experimental Relacionado

Updated: May 4, 2026

Use of the Protease Fluorescent Detection Kit to Determine Protease Activity

Use of the Protease Fluorescent Detection Kit to Determine Protease Activity

Published on: August 4, 2009

La proteína cdc25 contiene una actividad fosfatasa intrínseca

W G Dunphy¹, A Kumagai

¹Division of Biology, California Institute of Technology, Pasadena 91125.

|October 4, 1991

Resumen

La proteína cdc25 inicia la mitosis mediante la desfosforilación de la proteína quinasa cdc2. Este estudio demuestra que cdc25 funciona como una tirosina fosfatasa, catalizando la desfosforilación de varios sustratos de forma independiente.

Área de la Ciencia:

Biología celular Biología celular.
Biología Molecular Biología Molecular
La bioquímica es la bioquímica.

Sus antecedentes:

La proteína cdc25 es un regulador clave que controla la entrada en la mitosis.
Funciona desencadenando la desfosforilación de tirosina de la proteína quinasa cdc2, un paso crítico en la progresión del ciclo celular.

Objetivo del estudio:

Para investigar la actividad enzimática de la proteína cdc25 aislada.
Determinar si cdc25 posee actividad intrínseca de la fosfatasa y caracterizar esta actividad.

Principales métodos:

Evaluación de la desfosforilación de sustratos modelo como el fosfato de p-nitrofenilo y los péptidos fosforilados por tirosina por la proteína cdc25 aislada.
Analizando la cinética de la reacción y la sensibilidad a los inhibidores (vanadato de sodio, N-etilmaleimida) y las condiciones (agente reductor, quelantes metálicos).
Utilizando la mutagénesis dirigida al sitio para alterar un residuo de cisteína conservado y evaluar su impacto en la actividad de la fosfatasa.

Principales resultados:

La proteína cdc25 aislada catalizó efectivamente la desfosforilación de múltiples sustratos de la fosfatasa.
Las características de la reacción, incluyendo el requisito de agentes reductores y la sensibilidad al vanadato de sodio, reflejaban las de las fosfatasas de tirosina conocidas.
El tratamiento con N-etilmaleimida y la mutación de un residuo de cisteína conservado abolieron la actividad de la fosfatasa, destacando el papel de este residuo.

Conclusiones:

La proteína cdc25 posee actividad intrínseca de la tirosina fosfatasa.
Esta actividad es crucial para su papel en la regulación del ciclo celular y la entrada en la mitosis.
La proteína cdc25 puede funcionar como una tirosina fosfatasa independientemente de otras proteínas.

Más Videos Relacionados

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay

Published on: May 3, 2018

Identification of Nucleolar Factors During HIV-1 Replication Through Rev Immunoprecipitation and Mass Spectrometry

Identification of Nucleolar Factors During HIV-1 Replication Through Rev Immunoprecipitation and Mass Spectrometry

Published on: June 26, 2019

Videos de Conceptos Relacionados

Conservation of Protein Domains Over Different Proteins

Conservation of Protein Domains Over Different Proteins

Protein domains are small structurally independent units that are part of a single amino acid chain. Although these domains are often structurally independent, they may rely on synergistic effects to perform their functions as part of a larger protein. Protein domains may be conserved within the same organism, as well as across different organisms.
A limited set of protein domains often duplicate and recombine during evolution. These domains can be organized in different combinations to...

Covalently Linked Protein Regulators

Covalently Linked Protein Regulators

Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein....

Allosteric Proteins-ATCase

Allosteric Proteins-ATCase

Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis...

Anaphase Promoting Complex

Anaphase Promoting Complex

The stepwise destruction of specific proteins is necessary for the progression and completion of the cell cycle. Such proteins are ubiquitinated by ubiquitin ligases and then subsequently destroyed by the proteasome. The SCF (Skp1/Cullin/F-box) and the anaphase-promoting complex (APC) are two important ubiquitin ligases involved in cell cycle progression. While SCF is active throughout the cell cycle, APC gets activated during metaphase to anaphase transition. Cdc20 or Cdh1 binds to APC and...

Caspases

Caspases

Caspase, a family of cysteine proteases, serve as effectors in apoptosis. The ced3 gene in C.elegans was first identified to be involved in apoptosis. This gene encodes the ced-3 caspase that is similar to the interleukin-1-beta converting enzyme or ICE in mammals. In addition to apoptosis, caspases also function in the inflammatory response. Inflammatory caspases are essential in activating pro-inflammatory cytokines that recruit immune cells and block the replication of pathogens inside...

Bacterial Protein Maturation

Bacterial Protein Maturation

Bacterial protein maturation is a tightly regulated process that ensures newly synthesized polypeptides achieve correct functional conformations. This maturation involves a series of modifications, folding events, and quality control steps, often assisted by specialized chaperone proteins.N-Terminal ModificationsThe maturation of bacterial polypeptides begins cotranslationally as the polypeptide exits the ribosome. The first amino acid, N-formylmethionine (fMet), is typically modified at the...