Talk:Signal transduction

I have added a new intro/overview section for the article, I drew on material from Cosma Shalizi's "Signal transduction" Notebook from 2003-01-20 (http://bactra.org/notebooks/signal-transduction.html). It is used under the GFDL with permission, see Talk:Self-organization for GFDL-related correspondence with author. It probably need more work to be integrated better, some of the material might be relevant for the "Processing of environment signals" section. -- Lexor 11:15, 18 Aug 2003 (UTC)

Comments and suggestions for refactoring the introduction

The former revision (http://en.wikipedia.org/w/wiki.phtml?title=Signal_transduction&oldid=1901059) of this article had this introduction:

In biology, signal transduction describes the uptake of environmental signals by cells, the intercellular communication between cells in a multicellular organism, and the signal recognition, transmission, and resulting action within a cell. A typical signal transduction pathway consists of the following steps:

1. Biosynthesis of a hormone
2. Storage and secretion of the hormone.
3. Transport of the hormone to the target cell.
4. Recognition of the hormone by the hormone receptor protein, leading to a conformational change.
5. Relay and amplification of the signal that leads to defined biochemical reactions within the target cell. The reactions of the target cells can, in turn, cause a signal to the hormone-producing cell that leads to the down-regulation of hormone production.
6. Removal of the hormone.

The signal transduction can be altered at any of these steps. The single most important mechanism to do this is phosphorylation.

An edit by User:Hideshi changed this to (after some copyedits for spelling and grammar by me) the current edit:

In biology, signal transduction refers to the transformation of the extracellular physiochemical signals into intracellular signals. Extracellular signals are generally ligands of transmembrane receptors and are generally derived from either other cells or the environment (with the exception of autocrine factors), while an intracellular signal consists of a series of chemical interactions in either the cellular membrane or the intracellular space, or from the cellular membrane to the intracellular space. Generally autocrine factors are secreted from the cell and lose the distinction from those from the neighbouring cells.

Some typical examples of extracellular signals to which unicellular organisms respond include nutrients and related chemicals, while signals to cells in vertebrates organisms include photons, hormones, growth factors, cytokines, interleukins, neurotransmitters and the various ligands of the olfactory and gustatory receptors. Most extracellular chemical signals are water-soluble and membrane impermeable. These molecules act as ligands for transmembrane receptors and cause a structural change in these receptor molecules, which then induces the intracellular signalling phase. Typical examples of membrane permeable and extracellular signals are steroid hormones. Steroids hormones first diffuse into the cell membrane and then bind to their receptors, which are usually located in the cell nucleus.

Intercellular signalling molecules in eukaryotic cells include heterotrimeric G protein, small GTPases, cyclic nucleotides, such as cAMP and cGMP, calcium ion, phophoinositide derivatives, such as Phosphatidylinositol-triphosphate(PIP₃), Diacylglycerol (DAG) and Inositol-triphosphate (IP₃), and various protein kinases and phosphatases. Intracellular signalling usually leads to certain cellular responses, such as the regulation of gene expression, the modulation of signal transduction pathways, chemotaxis and morphological changes.

While I appreciate the detailed nature of the description here, it seems to have lost some of the clarity and relatively non-technical nature of the earlier version of the introduction. I suggest that we merge some of the above edit by Hideshi into the original edit of the page, and where it is not possible to merge, we can relocate the rest to the next section. We might also want to consider the Overview and context section as well in this refactoring. --Lexor 10:19, 8 Dec 2003 (UTC)

I see Lexor's points. My intension was to bring some generality to the discription. Please go ahead and be bold in editing. --Hideshi 8 Dec 2003

Receptor page

Receptor (proteomics) now contains a list of receptors. Please list any pages you know on that list, because it's presently a bit messy. JFW | T@lk 20:24, 14 Apr 2004 (UTC)