Intercellular communication

Intercellular communication refers to the various ways and structures that biological cells use to communicate with each other directly or through their environment. Different types of cells use different proteins and mechanisms to communicate with one another using extracellular signalling molecules. Components of each type of intercellular communication may be involved in more than one type of communication making attempts at clearly separating the types of communication listed somewhat futile. The sections are loosely compiled from various areas of research rather than by a systematic attempt of classification by functional or structural characteristics. Cell signaling Single celled organisms will sense their environment to seek food and may send out signals to other cells to behave symbiotically or reproduce. A classic example of this is the slime mold. The slim mold shows how intercellular communication with a small molecule eg.cyclic AMP allows a simple organism to form from an organized aggregation of single cells. Research into cell signalling investigated a receptor specific to each signal or multiple receptors potentially being activated by a single signal. It is not only the presence or absence of a signal that is important but also the strength. Using a chemical gradient to coordinate cell growth and differentiation continues to be important as multicellular animals and plants become more complex. This type of intercellular communication within an organism is commonly referred to as cell signalling. This type of intercellular communication is typified by a small signalling molecule diffusing through the spaces around cells, often relying on a diffusion gradient forming part of the signalling response. Cell junctions Complex organisms may have molecules to hold the cells together which can also be involved in intercellular communication. Some binding molecules are termed the extracellular matrix and may involve longer molecules like cellulose for the cell wall in plants or collagen in animals.