Summary
Highlights
The cytoskeleton is an assembly of multiple proteins that form a cellular framework, giving the cell its shape. Unlike our skeletal system, these protein assemblies are unstable and dynamic, constantly assembling and disassembling. There are three families of proteins that form the filaments of the cytoskeleton: microfilaments (or actin filaments), microtubules, and intermediate filaments. These filaments can be found throughout the cell, including inside the nucleus, in the cytoplasm, and under the cell membrane.
The cytoskeleton has several important roles: it gives the cell its shape, acts as a transport system within the cell (like intracellular rails), is responsible for cell movement on surfaces and muscle contraction, and is crucial for the transfer of messenger RNAs from the nucleus to the cytoplasm, as well as for enzymatic and metabolic activity.
Intermediate filaments are the most stable and rigid filaments in the cell. They are found around and inside the nucleus, where chromatin and DNA condense. They also form a network in the cytoplasm and under the cell membrane. Different types of intermediate filaments exist depending on the cell type. This is important information as it can indicate the origin of a cell and the organ it comes from. This information is particularly useful in cancer diagnosis to determine the origin of cancerous cells by identifying the specific type of intermediate filament present (e.g., lung, liver, prostate, or central nervous system).