Related Experiment Video
Updated: Aug 8, 2026
10:27
Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells
Published on: March 9, 2012
Physiological modulation of rabphilin phosphorylation
D L Foletti1, J T Blitzer, R H Scheller
1Howard Hughes Medical Institute, Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305-5428, USA.
Summary
Phosphorylation dynamically regulates rabphilin, a protein crucial for synaptic plasticity. This study reveals how rabphilin
Area of Science:
- Neuroscience
- Cell Biology
- Molecular Biology
Background:
- Protein phosphorylation is key to synaptic plasticity.
- Lack of specific reagents hinders study of phosphorylated proteins.
- Rabphilin's role in synaptic transmission is under investigation.
Purpose of the Study:
- To investigate the physiological modulation of rabphilin using phosphospecific antibodies.
- To understand the role of rabphilin phosphorylation in synaptic vesicle exocytosis.
Main Methods:
- Utilized phosphospecific antibodies to detect phosphorylated rabphilin.
- Analyzed rabphilin phosphorylation under basal and stimulated conditions.
- Investigated the dependence of phosphorylation on external Ca(2+) and Rab3a.
Main Results:
- Rabphilin phosphorylation on Ser-234 and Ser-274 is dynamically regulated by kinases and phosphatases.
- Phosphorylation is maximal under depolarizing conditions triggering exocytosis.
- Ca(2+) and Rab3a are critical for rabphilin phosphorylation.
- Phosphorylated rabphilin shows reduced membrane affinity.
Conclusions:
- Rabphilin is phosphorylated on synaptic vesicles by Ca(2+)-dependent kinases during exocytosis.
- Modulation of membrane association by phosphorylation may regulate synaptic vesicle cycling.
- This phosphorylation event could be crucial for vesicle mobilization in neurotransmission.
More Related Videos
08:55Rab10 Phosphorylation Detection by LRRK2 Activity Using SDS-PAGE with a Phosphate-binding Tag
Published on: December 14, 2017
12:49Human Peripheral Blood Neutrophil Isolation for Interrogating the Parkinson's Associated LRRK2 Kinase Pathway by Assessing Rab10 Phosphorylation
Published on: March 21, 2020
Related Concept Videos
01:14Rab Proteins
Rab proteins constitute the largest family of monomeric GTPases, of which 70 members are present in humans. Rab proteins and their effectors regulate consecutive stages of vesicle transport such as vesicle transport, docking, and fusion to the correct recipient membrane.
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
01:39Mechanism of Filopodia Formation
Filopodia are thin, actin-rich cellular protrusions that play an important role in many fundamental cellular functions. They vary in their occurrence, length, and positioning in different cell types, suggesting their diverse roles.
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
01:21Cell Polarization by Rho Proteins
Cell polarity is the asymmetric distribution of cellular and membrane components, making one side of the cell different from the other. This polarity is essential to many processes such as embryogenesis, axon migration, glucose transport across epithelial cells, and directional cell migration. A migrating cell responds to intracellular or extracellular signals via molecular cascades that reorganize the actin cytoskeleton to establish this polarity. In these cells, the Rho family proteins Cdc42,...
01:25Rab Cascades
Rab GTPases act in a regulated cascade during membrane fusion, helping the lipid bilayers mix. The Rab family of proteins are active when bound to GTP, and inactive when bound to GDP. Hence, they act as guanine nucleotide-dependent molecular switches. Rab-GTP recognizes and binds to long or short-range tethering proteins to capture the target vesicle. These tethers coordinate with SNAREs on the vesicle and the target membrane to assemble the trans SNARE complex that locks the mixing bilayers.
01:11IP3/DAG Signaling Pathway
Membrane lipids such as phosphatidylinositol (PI) are precursors for several membrane-bound and soluble second messengers. Specific kinases phosphorylate PI and produce phosphorylated inositol phospholipids. One such inositol phospholipids are the phosphatidylinositol-4,5 bisphosphate [PI(4,5)P2], present in the inner half of the lipid bilayer. Upon ligand binding, GPCR stimulates Gq proteins to turn on phospholipase Cꞵ. Activated phospholipase Cꞵ cleaves PI(4,5)P2 and produces two-second...
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,...