RE RE RE cytokines and taxonomy

Ralph M Bernstein ralph at ccit.arizona.edu
Sat Jan 28 19:30:43 EST 1995


Ok, re re re the taxonomy question.....

prev written in response to my posting:

>
>This is not true at all.  While steroid hormones are membrane soluble and
>act on receptors that are transcription factors, the peptide hormones
>(growth hormone, ACTH, insulin) and amino acid derivatives (serotonin, 
>dopamine, epinephrine) all work through membrane-bound receptors.

what is not true at all?  there is obviously a diff between steroid and
peptide hormones, but what i said obviously holds true for steroid hormones.  

>In addition, a number of cytokines have been shown to be non-critical for
>development.  Knockouts of IL-2 and IL-4 have no developmental (or
>immunological) defects.

these have not been shown to be non-critical.  the most obvious is and was
what i said, il-1.  the cytokines mentioned do have developmnental and
immunological effects! what articles did you read?  the fact is that cytokines 
have redundancys-back up systems (such as several sharing a receptor gamma
chain, or basic overlapping fuctions(eg il4/il6) and that just because when
these KOs were tested, the lack of those genes didn't turn out to be lethal
or have the incredibly detrimental effects expected  doesnot mean they do
not play a role in development!  Come on, no kidding some are non-critical
for development.  i was giving examples along the line of the first posting,
responding in kind-trying to give a little insight into how these system
work.    

>However, I agree that the immune system is a true organ system, and it
>and other hormones.
>BioKen
>-- 
>Ken Frauwirth (MiSTie #33025)       _           _
>frauwirt at mendel.berkeley.edu       |_) *    |/ (_ |\ |
>Dept. of Molec. & Cell Bio.        |_) | () |\ (_ | \|  
>Univ. of Cal., Berkeley          Push the button...someone :(


perhaps what i was saying missed its target?  these molecules (cytokines and
their receptors)  have been around for over 500 millions years.  the il1
system in vertebrates that i mentioned has a homolougous system in
drosophilia-even though the molecules do not participate in host immune
defense.  this implies that these molecules are conserved and that their
FUNCTION is conserved as a cell to cell signaling apparatus.  what i said
last time :


>Example, IL-1 is very important in normal
>development, as well as playing a role in the mature individual not
>necessarily always as the endogenous pyrogen. Back to the first point, the
>main role of  cytokines (in their immune system role) is to play a part in
>cell-to-cell communication.  
>
   Perhaps the classification system needs to be re-worked, but what the
orig poster wanted to know was how are these classified and why so
differently.  Obviously there is overlapping fuctions, but the cytokines
have been discovered in the pursuit of the understanding of the immune
system, so when a new immunesystem signal transducing/inducing messanger is
discovered it is grouped in that of the cytokines.  the overlap comes in
when a "cytokine" has a role that is non-cytokine traditional eg, in
development, or in drosophilia.  is this the role of a hormone, is the
release of a messanger from a non-"organ" the only defining factor?  
    let me hear you input into this.

ralph

Ralph M. Bernstein
Dept of Micro/Immuno
University of Arizona
Ph: 602 626 2585
Fx: 602 626 2100



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