TY - JOUR
T1 - Enhanced response of T lymphocytes from Pgap3 knockout mouse
T2 - Insight into roles of fatty acid remodeling of GPI anchored proteins
AU - Murakami, Hidekazu
AU - Wang, Yetao
AU - Hasuwa, Hidetoshi
AU - Maeda, Yusuke
AU - Kinoshita, Taroh
AU - Murakami, Yoshiko
PY - 2012/1/27
Y1 - 2012/1/27
N2 - Glycosylphosphatidylinositol (GPI) is a complex glycolipid that serves as a membrane anchor for many cell-surface proteins, such as Thy-1 and CD48. GPI-anchored proteins (GPI-APs) play important roles in many biological processes, such as signal transduction and cell-cell interaction, through their association with lipid rafts. Fatty acid remodeling of GPI-APs in the Golgi apparatus is required for their efficient association with lipid rafts, i.e., the unsaturated fatty acid at the sn-2 position of the PI moiety is exchanged for the saturated fatty acid by PGAP2 and PGAP3. To investigate the immunological role of the fatty acid remodeling of GPI-APs, we generated a Pgap3 knockout mouse. In this mouse, GPI-APs are expressed on the cell surface without fatty acid remodeling, and fail to associate with lipid rafts. Male Pgap3 knockout mice were born alive at a ratio lower than expected from Mendel's law, whereas the number of female mice followed Mendel's law. All mice exhibited growth retardation and abnormal reflexes such as limb grasping. We focused T cell function in these mice and found that T cell development in the absence of Pgap3 was normal. However, the response of T cells was enhanced in Pgap3 knockout mice in both in vitro and in vivo studies, including alloreactive response, antigen-specific immune response, and experimental autoimmune encephalomyelitis. Cross-linking of Thy-1 in wild-type cells inhibited the signal transduced by the T cell receptor (TCR), whereas cross-linking of Thy-1 in Pgap3 knockout cells enhanced the TCR signal. These results suggest that GPI-APs localized in lipid rafts may modulate signaling through the TCR.
AB - Glycosylphosphatidylinositol (GPI) is a complex glycolipid that serves as a membrane anchor for many cell-surface proteins, such as Thy-1 and CD48. GPI-anchored proteins (GPI-APs) play important roles in many biological processes, such as signal transduction and cell-cell interaction, through their association with lipid rafts. Fatty acid remodeling of GPI-APs in the Golgi apparatus is required for their efficient association with lipid rafts, i.e., the unsaturated fatty acid at the sn-2 position of the PI moiety is exchanged for the saturated fatty acid by PGAP2 and PGAP3. To investigate the immunological role of the fatty acid remodeling of GPI-APs, we generated a Pgap3 knockout mouse. In this mouse, GPI-APs are expressed on the cell surface without fatty acid remodeling, and fail to associate with lipid rafts. Male Pgap3 knockout mice were born alive at a ratio lower than expected from Mendel's law, whereas the number of female mice followed Mendel's law. All mice exhibited growth retardation and abnormal reflexes such as limb grasping. We focused T cell function in these mice and found that T cell development in the absence of Pgap3 was normal. However, the response of T cells was enhanced in Pgap3 knockout mice in both in vitro and in vivo studies, including alloreactive response, antigen-specific immune response, and experimental autoimmune encephalomyelitis. Cross-linking of Thy-1 in wild-type cells inhibited the signal transduced by the T cell receptor (TCR), whereas cross-linking of Thy-1 in Pgap3 knockout cells enhanced the TCR signal. These results suggest that GPI-APs localized in lipid rafts may modulate signaling through the TCR.
KW - Glycosylphosphatidylinositol-anchor
KW - Lipid raft
KW - Lipid remodeling
KW - Pgap3
KW - T cell signal
KW - Thy-1
UR - http://www.scopus.com/inward/record.url?scp=84862776850&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84862776850&partnerID=8YFLogxK
U2 - 10.1016/j.bbrc.2011.12.116
DO - 10.1016/j.bbrc.2011.12.116
M3 - Article
C2 - 22227195
AN - SCOPUS:84862776850
VL - 417
SP - 1235
EP - 1241
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 4
ER -