Rab11, a vesicular trafficking protein, affects endoreplication through Ras-mediated pathway in Drosophila melanogaster.
Rab11, a small monomeric GTPase associated with recycling endosomes, is a key molecule in the regulation of vesicular trafficking and is involved in the development and differentiation of many Drosophila tissues through interaction with diverse signaling pathways. In this study, we report for the first time that Rab11 affects endoreplication through a Ras-mediated pathway. Suppression of Rab11 activity in salivary glands, an endoreplicating tissue, leads to reduction in size of salivary glands with cells having a small nucleus. Endoreplication-regulating proteins, CycE, E2f1 and Gem, are also down-regulated in Rab11 knocked-down salivary glands suggesting that Rab11 has a role in the process of endoreplication, possibly indirectly through other pathways that regulate cell cycle progression. Ras signaling plays an important role in cell cycle progression through G/S phase transition. Ectopic expression of activated Ras in salivary glands of Rab11 down-regulated individuals rescues the small-sized glands to intermediate size. Furthermore, we observed altered localization of Ras in Rab11 down-regulated salivary glands. It is likely that the low level of endoreplication in the Rab11 down-regulated condition is Ras-mediated.
Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, 221 005, India.
Praween Kumar
PK
Choubey
Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, 221 005, India. jkroy@bhu.ac.in.
Jagat Kumar
JK
Roy
D000818:Animals; D002453:Cell Cycle; D015536:Down-Regulation; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000378:metabolism; D062951:Endoreduplication; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D009929:Organ Size; D059007:Polytene Chromosomes; D021381:Protein Transport; D012469:Salivary Glands / Q000166:cytology / Q000378:metabolism; D015398:Signal Transduction; D020691:rab GTP-Binding Proteins / Q000378:metabolism*; D018631:ras Proteins / Q000378:metabolism*; D000099193:rab11 GTP-Binding Proteins
D029721:Drosophila Proteins; D048049:Extracellular Signal-Regulated MAP Kinases; D020691:rab GTP-Binding Proteins; D018631:ras Proteins; C559123:Rab11 protein, Drosophila; D000099193:rab11 GTP-Binding Proteins
Endoreplication; Rab11; Ras; Salivary gland; Vesicular trafficking