3.4 Human MARCH1, MARCH2, and MARCH8 recognized Furin P domain
As the Co-IP assay and flow cytometry analysis indicated (Fig. 4A and
C), MARCH1 , MARCH2, and MARCH8 interacted with furin. Furin CD and P
domains are critically important for substrate cleavage. To identify
which domain was necessary for recognition by human MARCH1, MARCH2, and
MARCH8, we utilized two previously created furin mutants (29), i.e., the
furin CD deletion mutant (FRΔCD) and the furin P deletion mutant (FRΔP),
to perform Co-IP assay with these MARCH proteins. As shown in Fig. 5,
MARCH1, MARCH2, and MARCH8 could bind to both full-length furin and the
FRΔCD but rarely recognize the FRΔP, implying these MARCH proteins
recognize furin P domain.