Lecture

The Cytoskeleton

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In course

BIO-244: Physics of the cell

Living organisms evolve in a physical world: their cells respond to mechanics, electricity and light. In this course, we will describe the behavior and function of cells using physical principles. ...

Description

This lecture covers the structure, functions, and requirements of the cytoskeleton, a network of protein filaments essential for cell organization, shape maintenance, and movement. It explores the mechanical properties of cytoskeletal elements, such as actin and microtubules, and their dynamic organization within cells. The instructor discusses the process of cytoskeletal polymer growth, filament buckling, and the critical forces involved. Additionally, the lecture delves into the concept of treadmilling, where cytoskeletal filaments simultaneously grow at one end and shrink at the other. Various models for polymer growth and the dynamic instability of microtubules are also examined.

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Instructor

Alexandre Louis André Persat

Expertise bacterial biophysics and bioengineeringmicrofluidicscellular biomechanics Teaching & PhD PhD Students Jann Lukas Ledergerber, Dea Mariette Müller, Marin Paul Geoffroy Marie Ollagnon, Han-Yi Huang, Alice Pellegrino, Shiro Otaki, Chia-Ni Tsai, Po-Long Hsiao Past EPFL PhD Students Lorenzo Anton-Louis Talà, Xavier Pierrat, Tamara Rossy, Alice Cont, Jeremy Wong, Sourabh Monnappa Kuppanda Jafri, Tania Distler Past EPFL PhD Students as codirector Gabriele Gambardella Courses Fluid mechanics (for SV)

Official source

Related concepts (32)

Actin

Actin is a family of globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in muscle fibrils. It is found in essentially all eukaryotic cells, where it may be present at a concentration of over 100 μM; its mass is roughly 42 kDa, with a diameter of 4 to 7 nm. An actin protein is the monomeric subunit of two types of filaments in cells: microfilaments, one of the three major components of the cytoskeleton, and thin filaments, part of the contractile apparatus in muscle cells.

Cytoskeleton

The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is composed of similar proteins in the various organisms. It is composed of three main components, microfilaments, intermediate filaments and microtubules, and these are all capable of rapid growth or disassembly dependent on the cell's requirements.

Treadmilling

In molecular biology, treadmilling is a phenomenon observed within protein filaments of the cytoskeletons of many cells, especially in actin filaments and microtubules. It occurs when one end of a filament grows in length while the other end shrinks, resulting in a section of filament seemingly "moving" across a stratum or the cytosol. This is due to the constant removal of the protein subunits from these filaments at one end of the filament, while protein subunits are constantly added at the other end.

Microtubule

Microtubules are polymers of tubulin that form part of the cytoskeleton and provide structure and shape to eukaryotic cells. Microtubules can be as long as 50 micrometres, as wide as 23 to 27 nm and have an inner diameter between 11 and 15 nm. They are formed by the polymerization of a dimer of two globular proteins, alpha and beta tubulin into protofilaments that can then associate laterally to form a hollow tube, the microtubule. The most common form of a microtubule consists of 13 protofilaments in the tubular arrangement.

Cell junction

Cell junctions or junctional complexes, are a class of cellular structures consisting of multiprotein complexes that provide contact or adhesion between neighboring cells or between a cell and the extracellular matrix in animals. They also maintain the paracellular barrier of epithelia and control paracellular transport. Cell junctions are especially abundant in epithelial tissues. Combined with cell adhesion molecules and extracellular matrix, cell junctions help hold animal cells together.

Related lectures (32)

Microtubules: Structure, Function, and Regulation

Explores the structure, function, and regulation of microtubules, including forces involved in dynamics and pronuclear migration.

Cytoskeleton and Tensegrity

Explores the structure and functions of the cytoskeleton components for cell support and movement.

Cytoskeleton: Actin Filaments and Microtubules

Explores actin filaments, microtubules, monomers, proteins, dimer formation, and protein aggregation in the cytoskeleton.

Cytoskeleton: Cellular Organization and Function

Covers the composition and functions of the cytoskeleton within cells.

Cellular Cytoskeleton Components