Golgi functions of Drosophila Gorab are required in the male accessory gland to elicit post-copulatory behavior of the female

Gorab is a trans-Golgi associated protein that, when mutated in humans, is associated with Golgi dysfunction in the inherited disease gerodermia osteodysplastica. In Drosophila, however, Gorab also associates with the core centriole protein, Sas6, and gorab mutants exhibit both centriole duplication and basal body defects resulting in ciliary abnormalities and loss of coordination. The Golgi functions of Gorab in Drosophila have therefore remained unclear. Here we show that maximal levels of Gorab expression during Drosophila development are seen in the terminally differentiated main cells of the male accessory gland, where Gorab's major associations are with known Golgi proteins. Gorab null mutant accessory glands show aberrant organization of the Golgi cisternae, defective secretion of glycosylated proteins, and abnormal microcarriers of secreted proteins within the gland's lumen. By driving the neuronal expression of wild-type Gorab in gorab null mutants, we rescue the centriole duplication defects and restore coordination permitting development of male flies that can mate but still show accessory gland defects. Females mated with such males are unable to modify the post-copulatory behavior that normally prevents females from re-mating. We conclude that the defective Golgi in the accessory gland of these males is unable to deliver the secreted Sex-peptide to the ejaculate that is responsible for this behavioral pattern in the female.