I think what Vladimir is really asking for is some information-theoretical
definition of a cellular signal. It is true that we're always speaking of
e.g. "synapses transmit information from cell a to cell b" without having
any too specific idea about where the information actually is. The same
might be true for many kinds of cellular signals. Classical information
theory was made for telegraph lines, where the rules of encoding are known.
but we don't really know them for communication between cells. This might be
one reason for the difficulty. I'd be also interested in a general
definition of the concept.
Jan
----------
Im Beitrag <w6Jx5.39424$_e4.1862115 at typhoon.mw.mediaone.net>, "Richard
Norman" <rsnorman at mediaone.net> schrieb:
> "Vladimir Matveev" <vm_spb at my-deja.com> wrote in message
> news:8q769t$pvh$1 at nnrp1.deja.com...>> You are limited by reception processes, and I would like to receive a
>> general definition. The interactions in a cell can be of physical
>> nature too not only by molecular nature (molecule-receptor
>> interaction). In addition, signalling can has complex nature.
>> I was vague because I don't think there is a formal definition for this
> very general idea. Cells can have electrical connections and
> communicate by passing electrical signals to each other, or by
> physically pulling on another, but that is not what most people
> mean by "cell signaling". It is exactly the chemical method that
> is usually meant. And the interactions can indeed
> be very complex. That is why it is such a big subject now.
>>>>> In article <nMzx5.38973$_e4.1823900 at typhoon.mw.mediaone.net>,
>> "Richard Norman" <rsnorman at mediaone.net> wrote:
>> > "Vladimir Matveev" <vm_spb at my-deja.com> wrote in message
>> > news:8q4rn0$16r$1 at nnrp1.deja.com...>> > > Everybody in cell biology speak now about cellular SIGNALs. But who
>> > > knows the DEFINITION of a signal? Who given the definition? Where it
>> > > was published? Please, help me find the definition in the
>> literature.
>> > > Can YOU give the definition?
>> > > Thank everybody in advance.
>> > >
>> >
>> > Are you interested in the history or in what cell signaling is?
>> >
>> > For the definition, it refers to the process by which one cell can
>> > communicate with or control another. Now it usually means
>> > the method of communication where a molecule from one cell binds
>> > to a receptor in the other to initiate the control process. The usual
>> > example is hormonal control. For details, see Alberts et al,
>> > Molecular Biology of the Cell which has nice chapter on the subject.
>> >
>> > For the history, a cell biologist, biochemist, and physiologist
>> > in my department recall that it was a term certainly in use in
>> > the 80's and possibly earlier. I (the physiologist) thought it
>> > arose from Sutherland's work on 2nd messengers in the late 60's
>> > and 70's, but the biochemist thought it might have derived also
>> > from the signals involved in contact inhibition. All of us agreed
>> > that the phrase is so descriptive of the general phenomenon
>> > that it was not really a "new word" requiring a citation or
>> definition.
>> >
>> > I did find a 1969 edition of Dowben's "General Physiology, a
>> > Molecular Approach" where there was no mention of the concept.
>> > All my other ancient texts were long since discarded so I can't
>> > trace a time line.
>> >
>> >
>>>>>> Sent via Deja.com http://www.deja.com/>> Before you buy.
>>