Journal of Leukocyte Biology eBioscience full spectrum cell analysis
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Chaudhuri, S.
Right arrow Articles by Berger, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Chaudhuri, S.
Right arrow Articles by Berger, M.
(Journal of Leukocyte Biology. 2001;70:669-676.)
© 2001 by Society for Leukocyte Biology

Association of ARF and Rabs with complement receptor Type-1 storage vesicles in human neutrophils

Subhendu Chaudhuri*, Anoopa Kumar2 and Melvin Berger*

* Department of Pediatrics, Case Western Reserve University School of Medicine, and
{dagger} Division of Nephrology, Veterans Administration Hospital, Cleveland, Ohio

Correspondence: Melvin Berger, M.D., Ph.D., Division of Pediatric Immunology, Rainbow Babies’ and Children’s Hospital, Room 594, 11100 Euclid Ave., Cleveland, OH 44106. E-mail: mxb12{at}po.cwru.edu

During neutrophil activation, the properties of the cell are rapidly altered by increases in the surface expression of functionally important receptors and adherence molecules. At the same time, endocytic and phagocytic activities increase. These alterations require precise regulation of membrane and protein movement, which is achieved, at least in part, by bidirectional movement of small transport vesicles. GTP-binding proteins, including Rabs and ADP-ribosylation factors (ARFs), play critical roles in regulating vesicle trafficking in other types of cells. The ability to immunoisolate the "secretory" vesicle subpopulation in which complement receptor type 1 (CR1) is stored allowed us to determine which types of low-molecular-weight GTP-binding proteins interact with these vesicles and under what conditions. CR1-containing vesicles from resting human neutrophils constitutively copurify with Rabs 3a, 4, and 5a, and reversibly bind an ARF, likely ARF1. ARF binding is dependent on free Mg2+ and is enhanced by GTP{gamma}S. Mg2+ at 0.4 µM is necessary for half-maximal binding of ARFs to CR1 storage vesicles. Artificial phospholipid vesicles and primary and secondary granules from human neutrophils do not bind ARFs themselves and do not compete for recruitment of ARFs to CR1 vesicles, suggesting that specific membrane environments and/or proteins on these vesicles stabilize the ARF-GTP-Mg2+ complex. Free Ca2+ at 300 nM does not inhibit ARF binding to CR1 storage vesicles, but 10 mM Ca2+ does reduce such binding. These findings suggest that ARF-GTP specifically and reversibly interacts with CR1 storage vesicles in human polymorphonuclear leukocytes and may play a role in regulating their transport.

Key Words: low-molecular-weight GTP-binding proteins • transport vesicles • phagocytosis






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2001 by the Society for Leukocyte Biology.