|
( Signal transduction)
In biology, signal transduction refers to any process by which a cell converts one kind of signal or stimulus into another. Most processes of signal transduction involve ordered sequences of biochemical reactions inside the cell, which are carried out by enzymes, activated by second messengers, resulting in a signal transduction pathway. Such processes are usually rapid, lasting on the order of milliseconds in the case of ion flux, or minutes for the activation of protein- and lipid-mediated kinase cascades, but some can take hours, and even days (as is the case with gene expression), to complete. The number of proteins and other molecules participating in the events involving signal transduction increases as the process emanates from the initial stimulus, resulting in a "signal cascade," beginning with a relatively small stimulus that elicits a large response. This is referred to as amplification of the signal. The earliest published scientific paper recorded in the MEDLINE database as containing the specific term "signal transduction" within its text was published in 1972.[1] Prior to 1977 articles can be found that use the term "signal transmission" or "sensory transduction" within their title or abstract.[2][3] However, it is not until 1977 that papers start to appear with the specific term "signal transduction" within their abstract, and 1979 before this specific term appears within a paper title.[4][5] One source attributes the widespread use of the term signal transduction to a 1980 review article by Rodbell.[6][7] As can be seen from the graph to the right, it is not until the late 1980s/early 1990s that research papers directly addressing signal transduction processes began to appear in large numbers in the scientific literature. The occurrence of a specific term within the title or abstract of a scientific paper is usually a good indicator that the paper addresses a specifically related area of research[citation needed]. While there may be considered to be a number of landmark or important discoveries in the field of signal transduction, such as the link made by Rodbell between metabolic regulation and the activity of GTP and GTP-binding proteins,[7] much of our current understanding of signal transduction processes is as a result of numerous contributions made to the field over many years by different research groups all over the world. The total number of scientific papers related to signal transduction published since 1st Jan 1977 up to the 31st December 2007 was 48,377 of which only 11,211 were reviews of other papers
|
