Many cell functions involve communication between cells via molecular signals that must be sent from one cell to be received by a target cell. suppose the signal to be sent is a small protein. where would you expect to find the protein in the golgi?

Lumen of the Golgi.

Explanation:

Golgi apparatus is a membrane-bound organelle of eukaryotic cells, and it is made up of a series of pouches called cisternae. This organelle is responsible for modifying, transporting and packaging proteins and lipids into vesicles which will be delivered to different targets of the cell.

The sent proteins arrive in clusters of fused vesicles and they are received at the cis face of the Golgi apparatus. They move along the microtubules of the cell through the vesicular-tubular cluster, which is a trafficking compartment that lies between the Golgi apparatus and the endoplasmic reticulum. When a vesicle cluster fuses with the cis membrane, the contents are delivered into the lumen of the cis face cisterna.