Dynein

Dyneins are special proteins in our cells that act like tiny machines. These machines, called motor proteins, move along thin strands inside cells called microfilaments. They use a chemical called ATP for energy, which helps the cell do its work.

Dyneins have many important jobs in a cell. They carry materials from one place to another, help cells divide, and make the hair-like structures on cells called cilia and flagella move. This movement is important for many processes in our bodies, like moving fluids through tiny tubes or helping cells split during growth.

Unlike most other motor proteins, dyneins move toward one end of the microfilaments, called the minus-end. This direction is important for many cell functions and is different from another type of motor protein called kinesin, which moves in the opposite direction. Thanks to dynein, our cells can keep working smoothly.

Classification

Dyneins are divided into two main groups: cytoplasmic dyneins and axonemal dyneins, also called ciliary or flagellar dyneins. Cytoplasmic dyneins have several types of chains, including heavy chains like DYNC1H1 and DYNC2H1, and various intermediate and light chains. Axonemal dyneins also include several heavy chains such as DNAH2 and DNAH3, along with intermediate, light intermediate, and light chains. These different types help dyneins do important work inside cells.

Function

Axonemal dynein helps move tiny hair-like structures called cilia and flagella. These structures help many living things move and sense their environment.

Cytoplasmic dynein is found in most animal cells. It helps move important parts inside the cell, like organelles and packages of materials called vesicles. It also helps during cell division by positioning structures that separate chromosomes. Dynein moves along tiny tracks inside cells, carrying materials from one place to another.

Structure

Each dynein molecule is made of many smaller parts called polypeptides. There are two main types: cytoplasmic dynein and axonemal dynein. Both have similar parts but also some unique ones.

Cytoplasmic dynein helps move things inside cells. It has heavy chains that create movement, intermediate chains that attach to cargo, and light chains. Axonemal dynein is found in structures like cilia and flagella, helping them move by sliding microtubules past each other. This movement lets cells push themselves forward or move particles.

History

The protein that helps cilia and flagella move was first found and named dynein in 1963. Twenty years later, scientists found another type of dynein inside cells.

Chromosome segregation during meiosis

During the first step of meiosis, homologous chromosomes move to opposite sides of the cell. This helps make sure each new cell has the right number of chromosomes. Usually, things called chiasmata help with this, but in some yeast, a protein called dynein can do it even without them. Parts of the dynein protein, such as Dhc1 and Dlc1, are important for this movement.