In article <92234.085803FORSDYKE at QUCDN.QueensU.CA> <FORSDYKE at QUCDN.QueensU.CA> writes:
>Continuing the discussion on intracellular self/not-self discrimination....
>> So, the next question I offer is: What evolutionary forces,
> acting by modifying the gene sequence, mould the encoded life-
> span of a particular gene product?
For some proteins for which a long half-life is necessary, evolution may have
selected for mutations that increased stability without severely affecting
function. Other ways that protein stability is increased are:
1. Compartmentalization - sequestering that protein away from
proteases.
2. Forming complexes - such as ribosomal proteins with rRNA, and
protein-protein complexes.
3. Modification - (hand-waving on my part) phosphorylation,
glycosylation, or other additions may increase stability.
On the other hand, some modifications may "mark" proteins
for degradation (and the resulting peptides would be presented
by MHC...).
Shiv
>>>>>>>>References: Forsdyke, D. (1992) Bionet.immunology 812 947edt
>>>>>>> Prasad, S. (1992) Bionet.immunology 814 1516gmt
>>>>>>> Forsdyke, D. (1992) Bionet.immunology 817 1757edt
>>>>>>> Prasad, S. (1992) Bionet.immunology 818 133gmt
>>>>>> Forsdyke, D. (1992) Bionet.immunology 818, 1616edt
>>>>> Prasad, S. (1992) Bionet.immunology 819, 405gmt
>>>> Forsdyke, D. (1992) Bionet.immunology 819 1019edt
>>>> Prasad, S. (1992) Bionet.immunology 819, 2019gmt
>> Forsdyke, D. (1992) Bionet.immunology 820, 858edt
>>> Prasad, S. (1992) Bionet.immunology 821, 56gmt
Forsdyke, D. (1992) Bionet.immunology, 858 edt
>[Footnote for sharp-eyed David K. whose note informs us of the previous
> advise he gave regarding citations in BioNet. To this I replied that
> eventually the paper and electronic media are going to merge and it is
> likely that the existing format in the paper literature will be generally
> adopted. In my opinion, the format David sets out is far too cumbersome.
> But this is another area of discussion and should not really continue under
> this heading.]
