RRC ID 67362
Author Segawa K, Suzuki J, Nagata S.
Title Constitutive exposure of phosphatidylserine on viable cells.
Journal Proc Natl Acad Sci U S A
Abstract Apoptotic cells are quickly recognized and engulfed by phagocytes to prevent the release of noxious materials from dying cells. Phosphatidylserine (PS) exposed on the surface of apoptotic cells is a proposed "eat-me" signal for the phagocytes. Transmembrane protein 16F (TMEM16F), a membrane protein with eight transmembrane segments, has the Ca-dependent phospholipid scramblase activity. Here we show that when lymphoma cells were transformed with a constitutively active form of TMEM16F, they exposed a high level of PS that was comparable to that observed on apoptotic cells. The PS-exposing cells were morphologically normal and grew normally. They efficiently responded to interleukin 3 and underwent apoptosis upon treatment with Fas ligand. The viable PS-exposing cells bound to peritoneal macrophages at 4 °C, but not at 25 °C. Accordingly, these cells were not engulfed by macrophages. When apoptotic cells were injected i.v. into mice, they were phagocytosed by CD11c(+)CD8(+) dendritic cells (DCs) in the spleen, but the PS-exposing living cells were not phagocytosed by these DCs. Furthermore, when PS-exposing lymphoma cells were transplanted s.c. into nude mice, they generated tumors as efficiently as parental lymphoma cells that did not expose PS. These results indicated that PS exposure alone is not sufficient to be recognized by macrophages as an eat-me signal.
Volume 108(48)
Pages 19246-51
Published 2011-11-29
DOI 10.1073/pnas.1114799108
PII 1114799108
PMID 22084121
PMC PMC3228483
MeSH Animals Anoctamins Apoptosis / physiology* Cell Line, Tumor Cell Transformation, Neoplastic Dendritic Cells / physiology Humans Mice Mice, Nude Phagocytosis / physiology* Phosphatidylserines / metabolism* Phospholipid Transfer Proteins / metabolism*
IF 9.412
DNA material pMXs-puro-mTMEM16A (RDB18742) pMXs-puro-mTMEM16B (RDB18743) pMXs-puro-mTMEM16C (RDB18744) pMXs-puro-mTMEM16D (RDB18745) pMXs-puro-mTMEM16E (RDB18746) pMXs-puro-mTMEM16F (RDB18747) pMXs-puro-mTMEM16G (RDB18748) pMXs-puro-mTMEM16H (RDB18749) pMXs-puro-mTMEM16J (RDB18750) pMXs-puro-mTMEM16F-long (RDB18751) pMXs-puro-mTMEM16F-D409G (RDB18752) pMXs-puro-mTMEM16F-D409G long (RDB18753) pMXs-puro-mTMEM16F-R211L (RDB18754) pMXs-puro-mTMEM16F-D409G/R211L (RDB18755) pEF-mTMEM16A (RDB18756) pEF-mTMEM16B (RDB18757) pEF-mTMEM16C (RDB18758) pEF-mTMEM16D (RDB18759) pEF-mTMEM16E (RDB18760) pEF-mTMEM16F (RDB18761) pEF-mTMEM16G (RDB18762) pEF-mTMEM16H (RDB18763) pEF-mTMEM16J (RDB18764) pEF-mTMEM16K (RDB18765)