Related Experiment Video
Updated: May 29, 2026
09:07
Genetic Manipulation of Cerebellar Granule Neurons In Vitro and In Vivo to Study Neuronal Morphology and Migration
Published on: March 17, 2014
Rac1 GTPase controls myelination and demyelination
Hwan Tae Park1, M Laura Feltri
1Department of Physiology; Mitochondria Hub Regulation Center (MHRC); College of Medicine; Dong-A University; Busan, South Korea.
Bioarchitecture
|September 17, 2011
Summary
Rac1 GTPase regulates actin polymerization in Schmidt-Lantermann incisures (SLI), controlling both myelin sheath formation and breakdown in peripheral nerves after injury.
Area of Science:
- Neuroscience
- Cell Biology
- Peripheral Nerve Biology
Background:
- Peripheral nerve injuries trigger Wallerian degeneration, characterized by myelin sheath fragmentation near Schmidt-Lantermann incisures (SLI).
- Schwann cell cytoskeletal changes are crucial for this demyelination process.
- Actin polymerization at SLI is essential for myelin sheath cleavage.
Purpose of the Study:
- To investigate the role of Rac1 GTPase in regulating actin polymerization at SLI during demyelination.
- To explore the connection between Rac-dependent actin dynamics and both myelination and demyelination in peripheral nerves.
Main Methods:
- Focus on molecular mechanisms of demyelination.
- Investigated the role of Rac1 GTPase and actin polymerization in Schwann cells.
- Analysis of cytoskeletal reorganization in response to peripheral nerve injury.
Main Results:
- Actin polymerization around SLI is a key step in myelin sheath fragmentation.
- Rac1 GTPase activity is critical for regulating this actin polymerization after injury.
- Rac-dependent actin polymerization influences both myelination during development and demyelination after injury.
Conclusions:
- Rac-dependent actin polymerization is a central mechanism controlling both myelination and demyelination in peripheral nerves.
- Findings provide insights into Schwann cell dedifferentiation and segmental demyelination processes.
- Highlights the dual role of Rac1 in peripheral nerve homeostasis and repair.
Related Concept Videos
01:24Small GTPases - Ras and Rho
Ras and Rho are small monomeric GTPases that act downstream of receptor tyrosine kinase (RTK) and regulate various cellular processes. These GTPases switch between active and inactive states by binding to guanine nucleotides.
Three regulatory proteins control their activity:
Three regulatory proteins control their activity:
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...
01:21Cell 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.
01:22Activation and Inactivation of G Proteins
Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high affinity and are together...
02:14GTPases and their Regulation
Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒ small G-proteins consisting of a single domain and large multi-domain G-proteins.
Large G-proteins, also known...
Large G-proteins, also known...