Journal Article

Promotion of the Uptake of PS Liposomes and Apoptotic Cells by a Product of Growth Arrest-Specific Gene, <i>gas6</i>

Yoshikazu Ishimoto, Kazumasa Ohashi, Kensaku Mizuno and Toru Nakano

in The Journal of Biochemistry

Published on behalf of The Japanese Biochemical Society

Volume 127, issue 3, pages 411-417
Published in print March 2000 | ISSN: 0021-924X
Published online March 2000 | e-ISSN: 1756-2651 | DOI: http://dx.doi.org/10.1093/oxfordjournals.jbchem.a022622
Promotion of the Uptake of PS Liposomes and Apoptotic Cells by a Product of Growth Arrest-Specific Gene, gas6

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Gas6, a ligand of receptor tyrosine kinases Axl, Sky, and Mer, potentiates cell proliferation and prevents cell death. It also contains γ-carboxylglutamic acid residues that mediate the interaction of some blood coagulation factors with negatively charged phos-pholipids. In our previous study, we demonstrated that Gas6 specifically binds to phos-phatidylserine (PS) and links Axl-expressing cells to the PS-coated surface. In this study, to further understand the biological role of the interaction of Gas6 with PS, we examined the effect of Gas6 on the uptake of PS liposomes by macrophages. In vitro phagocytosis studies showed that Gas6 enhanced the uptake of PS liposomes approximately threefold and that the interaction of Gas6 with the surface of macrophages was essential for this enhancement. Analyses of the mechanism of the uptake of PS liposome suggested that Gas6 interacts with PS liposome via its N-terminal Gla domain and with macrophages via its C-terminal domain. Like that of PS liposomes, the uptake of apoptotic cells by macrophages was also enhanced, approximately twofold, in the presence of Gas6. These findings suggest that Gas6 may help phagocytic cells recognize cells with PS exposed on their surfaces, which is considered to be one of the mechanisms for clearing away dying cells. Thus, Gas6 may play a critical role in homeostasis by facilitating the clearance of PS-expressing cells.

Keywords: Axl; Gas6; macrophage; phagocytosis; phosphatidylserine

Journal Article.  0 words. 

Subjects: Biochemistry

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