H., Endo, T., Yamamoto, K. & Obinata, T. (1990) Sequence of cDNAs
Encoding Actin Depolymerizing Factor and Cofilin of Embryonic Chicken
Skeletal Muscle: Two Functionally Distinct Actin-Regulatory Proteins
Exhibit High Structural Homology. Biochemistry. 29, 7420-7425.
Two actin-regulatory proteins of 19 and 20 kDa are involved in the
regulation of actin assembly in developing chicken skeletal
muscle. They are homologous with actin depolymerizing factor (ADF)
and cofilin, a pH-dependent actin-modulating protein, which were
originally discovered in chicken and mammalian brain respectively.
In this study, full-length cDNA clones were isolated by screening a
library constructed from poly(A+) RNA of embryonic chicken skeletal
muscle with the antibodies specific for each protein, and their complete
sequences were determined. The chicken cofilin cDNA encoded a
protein of 166 amino acids, the sequence of which had over 80% identity
with that of porcine brain cofilin. The amino acid sequence of the
ADF was 165 amino acids and showed about 70% identity with either
chicken or mammalian cofilin, in spite of the fact that ADF and cofilin
are functionally distinct. Like chicken and mammalian cofilin, ADF
and cofilin shared a hexapeptide identical with the amino-terminal
sequence of tropomyosin as well as the regions homologous to other
actin-regulatory proteins, including depactin, gelsolin, and
profilin. The overall nucleotide sequences and Southern blot
analysis of genomic DNA, however, indicated that the two proteins were
derived from different genes.
This paper appeared back to back with a paper from Jim Bamburg's group (Adams
et al, 1990 )
in which chick brain ADF was sequenced. While both these papers
were in press, the sequence of pig brain ADF was published (Moriyama
et al, 1990).
At the time that this papers were written, it was generally believed
that ADF was not pH sensitive and that cofilin was because of a paper
that reported this . However, it became apparent that both
proteins are pH sensitive (Hayden
et al, 1993; Hawkins
et al, 1993)
and that there are only slight differences in their activity (Yeoh
et al, 2002).
The sequence similarity noted in the C terminus of chick ADF/cofilin to
gelsolin, fragmin and profilin have turned out to be spurious. The
sequences reported in this paper have been deposited in GenBank under
accession numbers J02915.