(A) Comparison of amino acid sequences of APM-1,
UNC-101, APM-2, and mouse AP47. The amino acids that are conserved in
the three APM-1 homologs are in bold and shaded letters, and the
asterisks underneath the sequences represent the amino acids conserved
in all four proteins. Some of the amino acids are conserved in all four
proteins, but others are conserved only in the AP-1 medium chains. (B)
Diagram showing the evolutionary relationship among medium chains of
clathrin AP complexes. Medium chains of all four types of complexes are
compared. The circle on the center indicates a hypothetical ancestral
medium chain gene. The prefix C indicates the sequence is from
C. elegans, H from humans, R from rat, M from mouse, D
from Drosophila, Y from yeast. For example, CAPM-1 is C.
elegans APM-1 and DAPM-1 is the Drosophila APM-1 homolog. This
dendrogram clearly shows that APM-1 is a member of the AP-1 medium
chain family, together with UNC-101. (C) Genomic structures of the
apm-1 and unc-101 genes. Exons are drawn
as thick lines, and introns are drawn as thin lines outside the exon
structures. Introns are not drawn in scale. The numbers indicate the
numbers of nucleotides in each exon or intron.