Adding membrane signal to cytoplasmic protein

[Shaun D. Black]

gchacko at magnus.acs.ohio-state.edu (George W Chacko) wrote:

> In article <1994Oct25.210606.8762 at mbcf>,  <mhughes at mbcf.stjude.org> wrote:
> 
> > You might want to try adding a ras-like CAAX sequence to the
> > c-terminus of you protein.  I don't know if this has been done
> > successfully before or not, but I'm almost positive that this sequence
> > alone comprizes the entire myristilation signal for ras and many
> > other,proteins, and may work for armadillo.
> 
> Correct me if I'm wrong but is a CAAX box really a myristilation
> signal? I was underthe impression that myristilation is directed by a
> glycine in position 2 (ref: Marilyn Resh's recent minireview in Cell).
> 

To the best of my knowledge, the motifs CXXX, CXC, and CC are polyiso-
prenylation signals if near the COOH-terminus of a protein.  That is,
farnesyl- or geranylgeranyl- moieties will be added, thereby promoting
membrane binding due to the hydrophobic lipid pendant thioesterified
to the Cys residue.  In CXXX, there is a preference for the first two X
positions to be aliphatic residues (like Ala), but the third X and the
X in CXC can be almost anything for proper signal function.  If you're
interested in some further info about prenylation you might want to see
BBRC 186, 1437-1442 (1992) [and references therein].  Best regards,  Shaun

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  = Shaun D. Black, PhD   | Internet address:     shaun at jason.uthct.edu = 
  = Dept. of Biochemistry | University of Texas Health Center, at Tyler = 
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