Cytoskeleton & cellular mechanics
The eukaryotic cytoskeleton—actin filaments, microtubules, and intermediate filaments—powers migration, division, vesicular traffic, and tissue morphogenesis. In muscle cells, filaments organize into sarcomeres and subsarcolemmal networks that couple to excitation–contraction, mechanotransduction, and diseases such as cardiomyopathies and dystrophinopathies.
1. Key targets
Actin module
- ACTB / ACTG1
Major cytoplasmic and sarcomeric β/γ-actin isoforms; thin filaments with tropomyosin and troponin.
- Arp2/3 & formins
Branching versus elongating nucleators; cooperate with Rho-family effectors in lamellipodia and stress fibers.
- cofilin / profilin / gelsolin
Severing/nucleation balance; LIMK–cofilin is a hotspot for integrin–RTK migration readouts.
Microtubules & motors
- TUBA / TUBB、MAPs、EB 蛋白与 +TIP 复合物
- Kinesins / dynein: vesicle traffic, spindles, axonal transport
IFs & sarcomeric scaffolds
- DES, vimentin, keratins (tissue-specific)
- TTN, NEB, DMD, α-actinin: Z-disk and membrane–ECM coupling
2. Suggested experimental readouts
Mind fixatives for phalloidin compatibility; pair phospho readouts with totals and inhibitor/myosin controls.
- F-actin quantification: phalloidin / LifeAct / SiR-actin (resolution vs phototoxicity trade-offs)
- Acetyl-α-tubulin / detyrosinated tubulin; EB1 comets (+TIP dynamics)
- p-cofilin, p-MLC2 (Thr18/Ser19), p-FAK (Y397)—migration–contractility coupling
- Muscle: TnI/TnT, p-PLN (Ser16), RyR2 clusters, desmin networks (model-dependent)
3. Regulation of actin cytoskeleton
Rho-family GTPases (RHOA, RAC1, CDC42) act as molecular switches translating adhesion and RTK inputs into Arp2/3, formin, cofilin, and non-muscle myosin II activities. KEGG pathway hsa04810 summarizes a canonical topology.
| GTPase | Representative effectors | Cytoskeletal phenotype | Practical notes |
|---|---|---|---|
| RHOA | ROCK → MLC phosphorylation; formins (mDia) | Stress fibers, mature focal adhesions, cortical actomyosin | Y-27632 / H1152 |
| RAC1 | WAVE / Arp2/3; PAK → LIMK → cofilin | Lamellipodia, ruffles, branched F-actin | CK666 / CK869 (Arp2/3) |
| CDC42 | WASP/N-WASP → Arp2/3; PAK | Filopodia, polarity, invasive protrusions | ML141 (tool CDC42 inhibitor) |
- Ena/VASP and formins cooperate to elongate bundled F-actin, functionally partitioning from Arp2/3 branched networks at the leading edge.
- Focal-adhesion–actin coupling: talin–vinculin–integrin mechanosensing with FAK/Src amplification of migration decisions.
4. Cytoskeleton in muscle cells
Striated muscle contracts via sarcomeres: α-actinin at Z-lines anchors thin filaments; A-bands contain myosin thick filaments; titin behaves as a molecular spring setting sarcomere length and passive tension. Desmin links Z-disks into a 3D lattice that stabilizes force transmission and organizes mitochondria.
The dystrophin–glycoprotein complex (DGC) links the cortical actin cytoskeleton to the extracellular matrix—critical for sarcolemmal stability; DMD mutations increase membrane fragility and disturb regeneration–fibrosis balance. Smooth muscle lacks canonical sarcomeres but uses MLCK/ROCK-driven regulatory light-chain phosphorylation, still relying on actomyosin and IF networks.
- Excitation–contraction coupling: L-type Ca²⁺ channels at T-tubules trigger RyR SR release → troponin conformational switch → tropomyosin movement exposes actin-binding sites.
- Intercalated discs & costameres: integrin–FAK and DGC parallel lateral force transmission; hypertrophy models often pair ANP/BNP with sarcomeric gene reprogramming readouts.
Cytoskeleton-related antibodies (curated)
Scored from product text using actin/microtubules/IFs, sarcomere & adhesion, Rho-family and Arp2/3 keywords—biased toward muscle and migration biology.
5. Product lines & on-site search
Primary & phospho antibodies
Actin/tubulin/keratin/desmin, troponins, tropomyosin, myosin, α-actinin, dystrophin, FAK/paxillin/talin, RhoA/Rac1/cdc42, p-cofilin, p-MLC2—WB/IHC/IF/live imaging per datasheet.
Tool compounds & dyes
Latrunculins, cytochalasins, jasplakinolide, nocodazole, paclitaxel, blebbistatin often pair with antibody readouts—mind phototoxicity and species differences.
6. Inhibitors & tool compounds (summary)
For research use; follow compound datasheets, phototoxicity limits, and ethics.
Sequester G-actin; depolymerize F-actin.
Barbed-end capping; blocks elongation.
Stabilizes F-actin; check fixation compatibility.
Arp2/3 inhibition; lamellipodia controls.
Formin-mediated elongation blockade.
ROCK inhibitor; common in PSC passaging—mind off-target cytoskeletal effects.
Myosin II ATPase inhibitor; migration / cytokinesis controls.
MT depolymerization / stabilization—pair with actin mechanical balance.
7. Pathway schematic
- Rho family → ROCK / PAK–LIMK–cofilin / Arp2/3 / formins
- Sarcomere: Z-line—thin—thick—titin elasticity
- DGC: sarcolemmal–ECM mechanical coupling
- MTs & IFs support organelle positioning
8. Pathway biology overview
The cytoskeleton is not a passive scaffold: it bidirectionally couples to signaling—mechanosensitive adhesions tune kinases, while remodeling feeds back on receptor distribution and membrane tension. Invasion, fibrotic contraction, and cardiac hypertrophy often co-evolve actomyosin tension with transcriptional programs.
- Cytokinesis: RhoA–ECT2–NMII contractile ring
- Cilia/flagella: axonemal microtubules + motor-driven trafficking
9. Related pathways on this site
10. External databases & modification resources
- KEGG: hsa04810 Regulation of actin cytoskeleton
- Reactome: Muscle contraction (muscle contraction & Ca²⁺ regulation)
- WikiPathways (search: Regulation of actin cytoskeleton)
- PhosphoSitePlus (MLC, cofilin, FAK sites, etc.)
11. References
Actin dynamics
- • Pollard TD, Cooper JA. (2009). Actin, a central player in cell shape and movement. Science. 326(5957):1208-12.
- • Ridley AJ. (2011). Rho GTPases and actin dynamics in membrane protrusions and vesicle trafficking. Trends Cell Biol. 21(11):638-46.
Muscle & disease
- • Gautel M. (2011). The sarcomeric cytoskeleton: who picks up the strain? Curr Opin Cell Biol. 23(1):39-46.
- • Ervasti JM. (2007). Costameres: the Achilles' heel of Herculean muscle. J Biol Chem. 282(50):36591-4.