stan is enriched to high levels at the interface between R8 and the two to three contacting interommatidial cells, whereas variable amounts accumulates at the interface between R3/R4 photoreceptor precurors and the five to seven contacting interommatidial cells.

stan is found in the region of the developing sex comb in the distal transverse row bristle and sex combs and to a lesser extent on the adjacent transverse row bristles.

stan is strongly expressed in all sensory cell bodies and in sensory and motor axons from early stage 13 through to late embryogenesis. It is also expressed in all primary tracheal branches including the dorsal trunk, dorsal branch, transverse connective, ganglionic branch, lateral trunk, and spiracular branch. Expression is restricted to the lateral and apical (luminal) surfaces of the tracheal cells except for the posterior lateral trunk where it is found over the whole tracheal surface.

stan protein is detected in the CNS and PNS of embryos at 18h AEL. In the CNS, it is detected in the motor axons that innervate the body wall muscles (hypodermal) and at the presynaptic sites of the neuromuscular junction. It is also detected in the nerve roots that exit the ventral nerve cord. Western blot analyses indicates that it is expressed in the larval CNS.

stan protein is detected in three layers of the distal medulla at 55 hr APF.

At 24 hr APF stan protein is strongly in the growth cones of photoreceptor cells R1-R6, and weakly expressed in neuronal cell bodies in the lamina. At 30 hr APF, stan is expressed unevenly in the growth cones of photoreceptor cells R1-R6 in the lamina plexus. By 46 hr APF, stan can no longer be detected in the growth cones or axons of photoreceptors. This expression pattern coincides with growth cone target selection. stan protein is also transiently expressed in photoreceptor cell R8 axons as they enter the optic lobe.

In third instar larvae, protein is strongly expressed in the lamina plexus where R1-R6 axons terminate and in the area of the medulla in which R7 and R8 axons terminate. Expression in photoreceptor cell axons is restricted to the growth cones. Expression was also observed in the lobula that correlates with the terminations of medullary cortical neurons. Expression in the medulla and lamina persists through pupal development with increased staining of lamina and medulla cortical neurons observed.

Between 0 and 4 hours after puparium formation protein is evenly distributed at the cell surface of apical sheath cells and does not display polarized localization.