Re: scientific american

From: CurtAdams@aol.com
Date: Mon May 29 2000 - 12:48:21 MDT


In a message dated 5/29/00 9:26:18 AM Pacific Daylight Time, hal@finney.org
writes:

> I wonder what happens to proteins which get built with errors? They won't
> self-assemble and will just float around, useless. There must be some
> other machinery which takes them apart, but it would seem hard to take
> apart an arbitrarily error-loaded protein.

Yes, there is machinery: chaperones recognize these defective proteins,
and ubiquinate them, which causes them to get disassembled in proteosomes.
I would guess there are other mechanisms too.

> Maybe everything in the cell
> gets periodically swept into a lysosome and dissolved?

Yes, pretty much everything in the cell turns over at a good clip. (Not all
in the lysosome; there are some other systems too). Presumably this
non-specific
system takes care of the goofs the specific systems (like the chaperones)
miss. But even they miss sometimes; look at Alzheimer's.



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