Inhibitory regulator of the Ras-cyclic AMP pathway. May function as a negative regulator of Ras85D/Ras1 in the sev signaling pathway. Acts cell autonomously in cone cell precursors as a negative regulator of R7 photoreceptor cell determination. Interacts with sty. In third instar larvae eye imaginal disk, expressed in cells posterior to the morphogenetic furrow, in all photoreceptor and cone cell precursors as well as in still uncommitted cells. Mutant flies display a highly irregular eye pattern, with ommatidia improperly oriented and occasionally fused. Most of these ommatidia contain extra cells that resemble R7 photoreceptor cell, characterized by small rhabdomere diameter, a central position in the distal half of the retina and expression of the R7-specific rhodopsin Rh4. The extra R7 cells are derived from cone cell precursors. In mutant wing, an additional longitudinal vein branches off the posterior crossvein, the wing veins widen at their junctions with the wing margins and wing vein material is found in between the longitudinal veins.