Figure 9.

Transphosphorylation between phot1 Molecules Promotes Receptor Internalization.

(A) and (B) Coexpression of a kinase-inactive version of phot1-GFP (phot1-GFP^D806N) with nonfluorescently labeled phot1^2xLOV1 (A) or phot1^I608E (B) shows that both these constitutively active forms of phot1 can induce internalization of phot1-GFP^D806N in darkness (as indicated by the white arrows).

(C) Fluorescence images of a kinase inactive version of phot1-GFP (phot1-GFP^D806N) coexpressed with nonfluorescently labeled phot1 in tobacco leaf epidermis show that phot1 can induce blue light–dependent internalization of phot1-GFP^D806N (as indicated by the white arrows).

(D) Fluorescence images of phot1-YN and phot1-YC coexpressed in tobacco leaf epidermis. Reconstitution of YFP fluorescence was only detected following blue light irradiation. Bright-field images are shown below. Internalization of phot1 is indicated (white arrows).

Bars = 20 μm.

[See online article for color version of this figure.]