Week 10 Lecture 3 - Cytoskeleton

What is cytoskeleton?

A system of protein filaments that functions in shape, and movement of things within the cell by motor proteins

What is the structure of microtubules?

Hollow tubes made of a-tubulin and B-tubulin. They have a plus end and a minus end, and elongation is rapid at the plus end. They grow from an organizing center called the centrosome.

State the motor proteins that use microtubules and how they use them

Motor proteins Dynein and Kinesin travel along microtubules using ATP, dynein going to the minus end and kinesin going to the plus end. They carry vesicles, organelles or cytoskeleton components.

What are the 2 systems microtubules are used to generate cell motility?

Mitotic spindle - an array of microtubules with proteins like motor proteins that functions in separating chromosomes during mitosis.

Cilia and flagella - structure of 9 microtubule pairs in a ring and 2 single microtubules in the center. Generate movement by dynein causing microtubules to slide past one another.

What is the structure of actin microfilaments?

Thin solid rods made of actin monomers. Monomers are added to the plus end and removed from the minus end. Myosin is the motor protein of actin microfilaments, using ATP to walk to the plus end.

What are 2 systems where actin microfilaments generate cell motility?

Muscle movements - In muscle cells, myosin proteins bundle together to form thick filaments.

Cytoplasmic streaming - the movement of cytoplasm within cells, driven by actin microfilaments to transport materials and facilitate cellular processes.