Cytoskeleton
CYTOSKELETON
- Filamentous structure which helps in maintaining the cell structure, change in cell shape and its associated functions.
- Made of 3 filaments –
- Microfilaments
- Intermediate filaments
- Microtubules
MICROTUBULES:
- Dynamic portion of cellular cytoskeleton.
- Hollow fine tubules made of protein “Tubulin”.
- Made of 3 globular subunits: α-, β- & γ-tubulin.
- γ-tubulin – Located in centrosome & has an important role in assembly.
- α- & β-tubulin – Polymerizing to form microtubules.
Properties of microtubules:
- Polar.
- Diameter: 25 nm
- Dynamic instability.
- Microtubule assembly utilizes GTP energy.
Functions:
- Determines cell shape by providing structural support.
- Aids in cellular movements – Locomotion & intracellular organelles movements.
- Necessary for formation & function of mitotic spindle.
- Major structural component of cilia, flagella & axon and dendrites.
INTERMEDIATE FILAMENTS:
- Very stable – Hence, important in maintaining cellular structural integrity
- Diameter – 10-12 nm.
- Important components included,
- Lamins.
- Keratins.
- Desmin – Used diagnostically in pathologic cases to indicate disorders of muscle origin.
- Neurofilaments.
MICROFILAMENTS:
- Made of 2 F-actin (filamentous actin).
- Actin – Most abundant protein in mammalian cells.
- Useful in muscular contraction.
- Diameter: 7 – 9.5 nm
- Microfilaments are abundant in Lamellipodia.
Exam Important
CYTOSKELETON
MICROTUBULES:
- Hollow fine tubules made of protein “Tubulin”.
Properties of microtubules:
- Polar.
- Dynamic instability.
- Microtubule assembly utilizes GTP energy.
Functions:
- Determines cell shape by providing structural support.
- Necessary for formation & function of mitotic spindle.
INTERMEDIATE FILAMENTS:
- Very stable
- Important components included,
- Lamins.
- Keratins.
- Desmin – Used diagnostically in pathologic cases to indicate disorders of muscle origin.
- Neurofilaments.
MICROFILAMENTS:
- Made of 2 F-actin (filamentous actin).
- Useful in muscular contraction.
- Microfilaments are abundant in Lamellipodia.
Don’t Forget to Solve all the previous Year Question asked on Cytoskeleton
