English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

RabD, a Dictyostelium Rab14-related GTPase, localizes in the endo-lysosomal pathway and contractile vacuole system of membranes. Cell lines expressing dominant-negative RabD were defective in endocytosis, endosomal membrane flow and homotypic lysosome fusion. In support of a role for RabD in fusion, cells overexpressing constitutively active RabD(Q67L) accumulated enlarged hydrolase-rich acidic vesicles ringed with GFP-RabD, consistent with RabD directly regulating lysosome fusion. To determine whether RabD also regulated phagocytosis and/or homotypic phagosome fusion (a process stimulated by many intracellular pathogens), cells overexpressing dominant-active (RabD(Q67L)) or dominant-negative (Rab(N121I)) RabD were analyzed microscopically and biochemically. The rate of phagocytosis was increased two-fold in RabD(Q67L)-expressing cells and reduced by 50% in RabD(N121I)-expressing cells compared with control cells. To examine the role of RabD in the formation of multiparticle phagosomes, we performed a series of pulse-chase experiments using fluorescently labeled bacteria and fluorescent latex beads. The rate of fusion of newly formed phagosomes was five times higher in the RabD(Q67L)-expressing cells and reduced by over 50% in RabD(N121I)-expressing cells as compared with control cells. GFP-RabD(Q67L) was found to ring multiparticle spacious phagosomes, which supports a direct role for this protein in regulating fusion. Inhibition of PI 3-kinase activity, which is known to regulate phagosome fusion in the wild-type cells, reduced the rate of phagosome fusion in RabD(Q67L+) cells, indicating that RabD acted upstream of or parallel with PI 3-kinase. We hypothesize that RabD and, possibly, Rab14, a related GTPase that associates with phagosomes in mammalian cells, are important regulators of homotypic phagosome and endo-lysosome fusion.

RabD, aDictyosteliumRab14-related GTPase, regulates phagocytosis and homotypic phagosome and lysosome fusion