High impact information on Rop

• Mutations in the Drosophila Rop gene suggest a function in general secretion and synaptic transmission [1].
• Taken together, these results suggest that ROP interacts with syntaxin in vivo and is a rate-limiting regulator of exocytosis that performs both positive and inhibitory functions in neurotransmission [2].
• Studies on heterozygote animals indicate that half the amount of wild-type ROP results in a dramatic decrease in evoked and spontaneous exocytosis [2].
• Characterization of four point mutations in ROP shows that they fall into two phenotypic classes [2].
• The Rop gene expression during embryogenesis is restricted to the central nervous system (CNS) and the garland cells, a small group of nephrocytes that takes up waste materials from the haemolymph by endocytosis [3].

Biological context of Rop

• The rop gene product is homologous to the Caenorhabditis elegans UNC-18 and the rat munc-18/n-Sec1/rbSec1 proteins, implicated in the final steps of neurotransmitter exocytosis in nerve terminals, and the bovine mSec1 protein implicated in the secretion of catecholamines in chromaffin cells [4].
• It is also expressed in specialized tissues in which intensive exocytic/endocytic cycles take place, including the garland cells, a small group of nephrocytes which take up waste materials from the hemolymph by endocytosis. rop is regulated by a bidirectional promoter shared with Ras2, a member of the R-ras/TC21 branch of the ras supergene family [4].
• The Drosophila Ras2 and Rop gene pair: a dual homology with a yeast Ras-like gene and a suppressor of its loss-of-function phenotype [3].
• We have sequenced 10.2 kb of DNA surrounding this gene pair and find that in addition to Rop and Ras2 there is another gene located within this DNA sequence [5].

Anatomical context of Rop

• Rop was detected in the outer membranes of the labyrinthine channels, and in the outer membranes of many vesicles located nearby the labyrinthine channels, but not in vesicles located in inner parts of the cell [4].

Other interactions of Rop

• In this study, we analyzed the ultrastructural localization of the Rop and Ras2 proteins in the garland cell [4].
• ROP, the Drosophila Sec1 homolog, interacts with syntaxin and regulates neurotransmitter release in a dosage-dependent manner [2].

References