Video Experimental Relacionado
Updated: Jul 17, 2026
14:18
Fluorescence-based Measurement of Store-operated Calcium Entry in Live Cells: from Cultured Cancer Cell to Skeletal Muscle Fiber
Published on: February 13, 2012
Inactivación del canal de calcio del retículo sarcoplásmico por la proteína quinasa
Nature
|October 22, 1992
Resumen
Los canales de liberación de calcio del músculo esquelético están inactivados por la fosforilación de proteínas, lo que sugiere un mecanismo de retroalimentación negativa. Esta inactivación dependiente del calcio es revertida por las fosfatasas y bloqueada por inhibidores específicos de la quinasa.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Molecular Biología Molecular
- Fisiología Fisiología Fisiología.
Sus antecedentes:
- El receptor de ryanodina (RyR) es un canal crítico de iones de calcio en el retículo sarcoplásmico (SR) del músculo esquelético.
- La entrada de RyR está modulada por el calcio, con complejos efectos de activación e inactivación específicos de la concentración y el tejido.
- Los niveles fisiológicos de calcio en el músculo esquelético pueden desencadenar la inactivación, lo que implica un papel de retroalimentación negativa.
Objetivo del estudio:
- Para investigar el mecanismo celular subyacente a la inactivación dependiente de calcio del receptor de ryanodina del músculo esquelético.
- Para determinar si la fosforilación de proteínas regula el comportamiento de entrada de un solo canal del receptor de ryanodina.
Principales métodos:
- Utilizó la técnica de la pinza de parche para estudiar el encierro de un solo canal del receptor de la ryanodina.
- Investigó los efectos de las condiciones permisivas para la fosforilación de proteínas en la actividad del canal.
- Se examinó el impacto de la aplicación de fosfatasa y los inhibidores específicos de péptidos en la inactivación del canal.
Principales resultados:
- Se ha demostrado que el canal de liberación de proteínas/calcio del receptor de ryanodina se inactiva en condiciones que promueven la fosforilación de proteínas.
- Se demostró que esta inactivación es reversible con la aplicación de fosfatasa.
- Se encontró que la inactivación es prevenida por un inhibidor de péptidos específico para la proteína quinasa II. dependiente de calcio/calmodulina.
Conclusiones:
- Proporcionó evidencia de una proteína quinasa endógena asociada con el receptor de ryanodina.
- Se concluyó que esta proteína quinasa regula el encierro del canal del receptor de ryanodina, mediando la inactivación dependiente del calcio.
- Apoyó un mecanismo de retroalimentación negativa para la liberación de calcio en la contracción del músculo esquelético.
Videos de Conceptos Relacionados
01:26Cross-bridge Cycle
As muscle contracts, the overlap between the thin and thick filaments increases, decreasing the length of the sarcomere—the contractile unit of the muscle—using energy in the form of ATP. At the molecular level, this is a cyclic, multistep process that involves binding and hydrolysis of ATP, and movement of actin by myosin.
01:21G-Protein Gated Ion Channels
GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory organs,...
Sensory organs,...
01:27Feedback Regulation of Calcium Concentration
Calcium is an essential signaling molecule required for various cellular functions. Calcium pumps and ion channels on cell and organellar membranes, such as those on the endoplasmic reticulum (ER), regulate calcium concentrations inside the cell. They remain closed, keeping the cytosolic calcium levels low at a resting state.
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
01:16Calmodulin-dependent Signaling
Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
01:29Relaxation of Skeletal Muscles
The period of muscle contraction primarily influences the duration of stimulation at the neuromuscular junction (NMJ), the presence of free calcium ions in the sarcoplasm, and the availability of energy or ATP to support contractions.
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open.
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open.
01:25Smooth Muscle Contraction
Smooth muscle contraction is a complex process vital for various bodily functions, from maintaining blood vessel tension to facilitating the movement of food through the digestive tract. Unlike striated muscles, smooth muscle contraction begins more slowly and lasts longer.
The onset of contraction is triggered by an increase in calcium ions within the sarcoplasm, similar to the process in striated muscle. However, smooth muscles have a relatively smaller reservoir of the sarcoplasmic...
The onset of contraction is triggered by an increase in calcium ions within the sarcoplasm, similar to the process in striated muscle. However, smooth muscles have a relatively smaller reservoir of the sarcoplasmic...