|
|
|
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
|
Fig. 4. The degrading activity of Arrow is specific to Frizzled2. (A,A')
Wingless stabilized by Dally-like, as shown in A, is only weakly reduced by
further addition of Arrow, as shown in A'. (B-B') Likewise, Arrow
does not degrade Wingless stabilized by Frizzled2GPI. (C-C') Expression
of a form of Frizzled2 that lacks most of the intracellular tail
(Frizzled2
C) causes Wingless accumulation at the cell surface (C, main
panel) and appears to reduce Wingless internalization (as seen at high
magnification in the inset; compare with
Fig. 2A'). As shown in
C', such accumulation is abrogated by Arrow overexpression. This result
provides indirect evidence that Arrow contains an endocytic (in addition to a
degradation) signal as it can promote the removal of
Frizzled2C-complexed Wingless from the cell surface. (D,D') A
form of Arrow that lacks amino acids 1477 to 1612 (ArrC) is deficient
in degradation activity. This is shown in an imaginal disc expressing
ArrC in the posterior compartment. A pulse of Frizzled2 expression
(from hs-Frizzled2) was induced 1.5 hours prior to fixation. (D) ArrC
expression detected with anti-HA; (D') the distribution of Wingless.
Double-headed arrows mark the extent of the Wingless range in the two halves
of the disc. In the posterior compartment, the domain where Wingless vesicles
are detected is expanded.
|
