Vladi, That is one kind of signal. there are others. cell binds to matrix
and moves. bacteria recognize aa and swim toward it via the proton engine.
biochemically there is a recognition event that is exemplified by
'cytokine binding to a cell receptor' which leads to a signal (technically
there is probably a threshold level of receptors that need to bind,
whether the threshold is governed by a % occupancy or simply post-binding
signal strengh can be argued but a recognitive step seems to be required
for the signaling to start.
Vladimir Matveev wrote:
> According to you, "a signal is the binding of the cytokine to the
> receptor". This definition is extremely limited. A cell has many other
> kind of signals.
>> ***
> In article <39C7A721.F373B041 at Mail.TJU.Edu>,
> Mark Haynes <Mark.Haynes at Mail.TJU.Edu> wrote:
> > Yo mismo n' moi aussi.
> > I was thinking of signalling from the biochemical angle and not
> really the
> > reciever angle. From the example Jay gave, to me the signal is the
> binding of
> > the cytokine to the receptor -- in a vacuum. by that i mean that
> its not
> > necessary for the recieving cell to respond. cytokine binds to a
> extracellular
> > receptor and a chain of events happens -- protein shape change, ion
> flux,
> > kinase/phosphatase activity and the like.
> >
> > Jay Mone wrote:
> >
> > > My definition of a cellular signal is any substance or process
> which occurs
> > > between two cells which results in a specific cellular response
> from one of
> > > the cells. For example, the release of a cytokine by one cell,
> which is
> > > taken up by a second cell, resulting in a specific response from
> the second
> > > cell. I don't know if I've ever seen the term defined. I'd be
> interested
> > > to know.
> > >
> > > Jay Mone'
> > >
> > > ---
> >
> >
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