Cytoskeleton and Cell Migration Lecture Review

Flashcards covering the basic principles, components, functions, and mechanisms of the cytoskeleton and cell migration, based on the provided lecture notes.

Who first proposed that the shape of cells was determined by a network of tubules forming a skeleton, later termed the cytoskeleton?

Nikolai Koltsov in 1903.

What does 'cyto' mean in the word 'cytoskeleton'?

'Cell'.

List four general functions of the cytoskeleton.

It provides shape and support, helps in vacuole formation, holds cell organelles in place, assists in cell signaling, and supports intracellular movements.

What are the three main components of the cytoskeleton?

Microfilaments (actin filaments), intermediate filaments, and microtubules.

What are microtubules primarily made of?

Globular protein subunits called α-tubulin and β-tubulin.

What are some key functions of microtubules?

They help cells resist compression, provide tracks for vesicle movement, pull replicated chromosomes apart during cell division, and are structural elements of flagella, cilia, and centrioles.

What are intermediate filaments made of, and what is their primary function?

They are made of several strands of fibrous proteins wound together, and their function is purely structural, bearing tension and anchoring organelles.

Which type of intermediate filaments are found in hair, skin, and nails?

Type I and Type II Keratins.

What is the primary role of Type III intermediate filaments like Vimentin, Desmin, and GFAP?

They play essential roles in tissue integrity, especially in muscles, nerves, and endothelial cells, helping cells maintain shape and flexibility.

What are neurofilaments (Type IV intermediate filaments) essential for?

They are essential for supporting axons in neurons, providing strength and stability, and regulating axon size for nerve transmission.

Which type of intermediate filaments are primarily made up of lamins and form the nuclear lamina?

Type V intermediate filaments.

What are microfilaments (actin filaments) composed of, and what are the two main forms?

They are composed of actin subunits, present as G-actin (globular monomer) or F-actin (filamentous polymer).

What must actin be bound to in order to assemble into its filamentous form and maintain structural integrity?

ATP.

What are motor proteins, and what is their general function?

Specialized proteins that move along the cytoskeleton, converting chemical energy into mechanical work for intracellular transport, cell division, and movement.

Name the three main types of motor proteins mentioned and the cytoskeletal track they use.

Kinesins and Dyneins move along microtubules, while Myosins move along actin filaments.

What is cell migration?

A vital process involving the orchestrated movement of cells in particular directions to specific locations, important for embryonic development, wound healing, and immune responses.

What are the five general steps of cell migration?

Protrusion of the membrane (lamellopodia), adhesion to the matrix, contraction of the cytoplasm, rear release and forward displacement, and integrin recycling.

Which type of cell migration involves cells changing shape by extending and retracting pseudopodia, typically seen in immune cells?

Amoeboid migration.

What is chemotaxis?

Directed cell migration in response to a chemical gradient.

What is durotaxis?

Migration directed by stiffness gradients in the surrounding tissue or substrate, where cells move toward stiffer areas.

What is the primary mechanism for leading-edge extension during cell migration?

Actin polymerization.

What is the difference between cell migration and cell invasion?

Migration generally involves directional movement and formation of lamellipodia without ECM degradation, whereas invasion involves ECM degradation and specialized structures like invadopodia/podosomes.

Name two common cell migration assays.

Wound Healing (Scratch) Assay and Boyden Chamber (Transwell) Assay.