A single protein of the ocular lens was intensely myristoylated following s
hort term incubation of cultured bovine lens epithelial cells and intact ra
t lenses with H-3-myristic acid. It was acidic (pI <5), about 19 kDa and pr
esent exclusively in the cytosol of both cultured epithelial cells and the
epithelium of the young rat lens. Fiber cell proteins were not labeled. The
myristoylated protein was not seen in the epithelium of the adult rat. Ess
entially no protein mass was evident in the 19-20 kDa range when samples of
the labeled-soluble protein were fractionated by either HPLC coupled with
SDS-PAGE-or 2D-electrophoresis. These findings suggest that the myristoylat
ed-soluble protein-of 19 kDa in lens (p19(L)) is a rapidly-turning over min
or protein likely associated with lens growth. The absence of any apparent
membrane association for a myristoylated protein appears unusual. The trace
nature of p19(L) has frustrated attempts at its identification by MALDI-MS
. (C) 1999 Academic Press.