...Michael J. Medlyn; Easton Maeder; Claire Bradley; Prasad Phatarpekar; Hyoungjun Ham; Daniel D. Billadeau ABSTRACT Natural killer (NK) cells have the ability to lyse other cells through the release of lytic granules (LGs). This is in part mediated by the small GTPase Rab27a, which was first...

... in eukaryotes. GDP/GTP exchange factors (GEFs) control Rab activation, and current models propose that localised and regulated GEF activity is important in targeting Rabs to specific membranes. Here, we investigated the mechanism of GEF function using the Rab27a GEF, Rab3GEP (also known as MADD), in melanocytes...

...Rajesh K. Singh; Wenjia Liao; Dhani Tracey-White; Chiara Recchi; Tanya Tolmachova; Sara M. Rankin; Alistair N. Hume; Miguel C. Seabra Neutrophil migration is vital for immunity and precedes effector functions such as pathogen killing. Here, we report that this process is regulated by the Rab27a...

... distribution from perinuclear melanosome aggregation in Rab27A-deficient melanocytes. However, the function of Mreg in melanosome transport has remained unclear. Here, we show that Mreg regulates microtubule-dependent retrograde melanosome transport through the dynein–dynactin motor complex. Mreg interacted...

... bodies (WPBs) at early (immature) and late (mature) stages in their biogenesis. Membrane proteins (P-selectin, CD63, Rab27a) were also studied in individual WPBs. In the ER, soluble secretory proteins were mobile; however, following insertion into immature WPBs larger molecules (VWF, Proregion, tPA...

...Toshihide Kimura; Yukiko Kaneko; Shogo Yamada; Hisamitsu Ishihara; Takao Senda; Akihiro Iwamatsu; Ichiro Niki Rab27a is involved in the control of membrane traffic, a crucial step in the regulated secretion. Typically, the guanosine triphosphate (GTP)-bound form has been considered to be active...

...Alistair N. Hume; Dmitry S. Ushakov; Abul K. Tarafder; Michael A. Ferenczi; Miguel C. Seabra Melanosome transport in melanocytes is a model system for the study of cytoskeletal regulation of intracellular transport. Melanophilin (Mlph) is a Rab27a- and myosin Va (MyoVa)-binding protein...

...Takashi Tsuboi; Mitsunori Fukuda Recent studies have suggested that two small GTPases, Rab3A and Rab27A, play a key role in the late steps of dense-core vesicle exocytosis in endocrine cells; however, neither the precise mechanisms by which these two GTPases regulate dense-core vesicle exocytosis...

... , melanosomes in the retinal pigmented epithelium (RPE) are distributed abnormally. In this investigation we detected many proteins in RPE cells that could potentially participate in melanosome transport, but of those tested, only myosin VIIa and Rab27a were found to be required for normal distribution. Two...

..., a linker protein between myosin-Va and Rab27A on the melanosome. The myosin-Va-GT-binding site in Slac2-a was mapped to the region (amino acids 147-240) adjacent to the N-terminal Rab27A-binding site, but it is distinct from the myosin-Va-exon-F-binding site (amino acids 320-406). The myosin-Va-GT·Slac2...

... Fluorescence (TIRF) microscopy to visualize the three-dimensional motions of secretory organelles near the plasma membrane in living endothelial cells. Weibel-Palade bodies (WPb), the large tubular storage organelles for von Willebrand factor, were labelled with Rab27a-GFP. By contrast, green fluorescent...