October | 2013 | The Culture of Biochemistry

Not only do I communicate with my fellow muscle cells but I can communicate with other cells through autocrine signalling, such as nerve cells. This occurs when a cell secretes signal molecules that can bind back to its own receptors. During my development, for example, once I am directed along a particular pathway of differentiation, I can secrete autocrine signals to myself that will reinforce this decision.

Cell producing a signaling molecule to which it responds.

Autocrine signaling is most effective when it is performed simultaneously by neighboring cells of the same type, and it is likely to be used to encourage groups of identical cells to make the same developmental decisions. As a result, the autocrine signaling mechanism is known as the “community effect”. Being that I am in close range to my fellow nerve cell, I am able to respond to a differentiation inducing signal which allows me to actively communicate with it, rather if I were alone and isolated. A group of us cells will produce a higher concentration of a secreted signal than if we were to work alone. When this signal binds back to a receptor on the same cell type, it encourages us, the cells to respond coordinately as a group.

http://www.ncbi.nlm.nih.gov/books/NBK26813/figure/A2751/?report=objectonly

Autocrine signalling.

We cells have several different ways of communicating with each other, which depend on which type of cell we’re communicating with and also how far away that cell is. We can communicate by direct contact with each other, by using short range signals, by using long range signals or even by complex message in the form of electrical signals. All cells receive signals via signal receptor proteins, which may be inside the cell or on the cell membrane and they have a high affinity for binding with signal molecules. Once these signal molecules bind to their specific receptors, a signal cascade is usually set off and the cell reacts to this. Muscle cells, such as myself, are immediately surrounded by other muscle cells and together we make up muscle tissue. In the neighbouring areas, a variety of of types of cells exist, such as blood cells and nerve cells and I communicate with them very often.

As a muscle cell, I am surrounded by cells of the same type and we communicate with each other via direct cell-cell interactions using a mechanism called Gap Junctions. Gap junctions are specialized tube-like junctions, filled with water, that can form between cells in direct contact with each other, connecting the cytoplasm of the cells. Using these gap junctions, I can communicate with other muscle cells around me by sending, or receiving, small signal molecules and/or ions that help in determining the process I, or others, have to perform, whether it is growth or work.

As a mature muscle cell, I can send signals directly to neighbouring cells thereby causing an effect or change in the internal composition in relation to the signals I send. For example, as muscle cells in the leg of Xenopus laevis, my neighbours and I must be able to utilize energy stores quickly and efficiently for the muscle to perform its function, which relates to movement in the organism. Therefore, we have many mitochondria in us to quickly produce energy for us to work. The mitochondria that we contain are signalled when they are needed to perform their function, mainly by an increase in Ca2+ levels inside of our cytoplasm. Using gap junctions, Ca2+ can be transferred from cell to cell easily and quickly and so can signal the start of work in many cells in a relatively short time.