Calcium signaling is the use of calcium ions (Ca2+) to communicate and drive intracellular processes often as a step in signal transduction. Ca2+ is important for cellular signalling, for once it enters the cytosol of the cytoplasm it exerts allosteric regulatory effects on many enzymes and proteins. Ca2+ can act in signal transduction resulting from activation of ion channels or as a second messenger caused by indirect signal transduction pathways such as G protein-coupled receptors.
The resting concentration of Ca2+ in the cytoplasm is normally maintained around 100 nM. This is 20,000- to 100,000-fold lower than typical extracellular concentration. To maintain this low concentration, Ca2+ is actively pumped from the cytosol to the extracellular space, the endoplasmic reticulum (ER), and sometimes into the mitochondria. Certain proteins of the cytoplasm and organelles act as buffers by binding Ca2+. Signaling occurs when the cell is stimulated to release Ca2+ ions from intracellular stores, and/or when Ca2+ enters the cell through plasma membrane ion channels. Under certain conditions, the intracellular Ca2+ concentration may begin to oscillate at a specific frequency.
Specific signals can trigger a sudden increase in the cytoplasmic Ca2+ levels to 500–1,000 nM by opening channels in the ER or the plasma membrane. The most common signaling pathway that increases cytoplasmic calcium concentration is the phospholipase C (PLC) pathway.
Many cell surface receptors, including G protein-coupled receptors and receptor tyrosine kinases, activate the PLC enzyme.
PLC uses hydrolysis of the membrane phospholipid PIP2 to form IP3 and diacylglycerol (DAG), two classic secondary messengers.
DAG attaches to the plasma membrane and recruits protein kinase C (PKC).
IP3 diffuses to the ER and is bound to the IP3 receptor.
The IP3 receptor serves as a Ca2+ channel, and releases Ca2+ from the ER.
The Ca2+ bind to PKC and other proteins and activate them.
Depletion of Ca2+ from the ER will lead to Ca2+ entry from outside the cell by activation of "Store-Operated Channels" (SOCs).
Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.
Couvre le processus de fertilisation, y compris la rencontre, la spécificité, l'unicité, la fusion, l'activation et la vague de calcium post-fertilisation.
Explore le développement de la vulve chez C. elegans et les voies de signalisation complexes impliquées dans l'induction et l'inhibition de l'expression des gènes.
La signalisation cellulaire est un système complexe de communication qui régit les processus fondamentaux des cellules et coordonne leur activité. La capacité des cellules à percevoir leur micro-environnement et à y répondre correctement est à la base de leur développement et de celui des organismes multicellulaires, de la cicatrisation et du système immunitaire, ainsi que de l'homéostasie tissulaire normale. Des dysfonctionnements dans le traitement de l'information cellulaire peuvent être responsables de maladies telles que le cancer, les maladies auto-immunes et le diabète.
Les récepteurs de la ryanodine RyR constituent une classe de canaux calciques dans diverses formes de muscles. Ce sont des homotétramères formés de 4 sous-unités identiques, insérées dans la membrane du réticulum sarcoplasmique. Chaque monomère comporte 4 hélices transmembranaires qui entourent un canal permettant la sortie des ions calcium Ca de la lumière du réticulum vers le cytoplasme. Leur ouverture est déclenchée par des concentrations micromolaires d'ions calcium ou par la ryanodine (mais inhibitrice à forte dose) ou la caféine.
Cell growth refers to an increase in the total mass of a cell, including both cytoplasmic, nuclear and organelle volume. Cell growth occurs when the overall rate of cellular biosynthesis (production of biomolecules or anabolism) is greater than the overall rate of cellular degradation (the destruction of biomolecules via the proteasome, lysosome or autophagy, or catabolism). Cell growth is not to be confused with cell division or the cell cycle, which are distinct processes that can occur alongside cell growth during the process of cell proliferation, where a cell, known as the mother cell, grows and divides to produce two daughter cells.
Presentation of selected signalling pathways with emphasis on both the mechanism of action of the molecules involved, molecular interactions and the role of their spatio-temporal organization within t
The course introduces students to a synthesis of modern neuroscience and state-of-the-art data management, modelling and computing technologies with a focus on the biophysical level.
Le but est de connaitre et comprendre le fonctionnement des systèmes cardiovasculaire, urinaire, respiratoire, digestif, ainsi que du métabolisme de base et sa régulation afin de déveloper une réflect
Native reactive electrophile species (RES) such as 4-hydroxynonenal (HNE) act as cellular signals through covalent modification of kinetically-privileged electrophile sensor proteins. Research efforts in the field focus mainly on identifying these sensor p ...
The phenomenon of allostery, a general property in proteins that has been heralded as "the second secret of life" remains elusive to our understanding and even more challenging to incorporate into protein design. One example of allosteric proteins with gre ...
EPFL2024
, ,
Recordings of the physiological history of cells provide insights into biological processes, yet obtaining such recordings is a challenge. To address this, we introduce a method to record transient cellular events for later analysis. We designed proteins t ...