TY - JOUR
T1 - Attachment of the PSGL-1 cytoplasmic domain to the actin cytoskeleton is essential for leukocyte rolling on P-selectin
AU - Snapp, Karen R.
AU - Heitzig, Christine E.
AU - Kansas, Geoffrey S.
PY - 2002/6/15
Y1 - 2002/6/15
N2 - P-selectin glycoproteln ligand-1 (PSGL-1) serves as the leukocyte ligand for P-selectin, and many of the structural features of its ectodomain required for interactions with P-selectin have been uncovered. In contrast, the function of the highly conserved PSGL-1 cytoplasmic domain has not been explored. Stable transfectants expressing similar levels of either wild-type PSGL-1 or truncated PSGL-1 in which only 4 cytoplasmic residues were retained (designated PSGL-1Δcyto), were analyzed. Transfectants expressing full-length PSGL-1 rolled well on P-selectin. In contrast, rolling was almost completely absent in cells transfected with PSGL-1Δcyto, even at low shear. Importantly, cells expressing truncated PSGL-1 were able to bind soluble P-selectin and to bind COS cells overexpressing P-selectin, demonstrating that the P-selectin binding site on the PSGL-1Δcyto transfectants was intact and was capable of recognizing P-selectin. Impaired rolling by PSGL-1Δcyto transfectants was not due to alterations in subcellular localization because both wild-type and truncated PSGL-1 had similar surface distributions on K562 transfectants. Treatment of cells expressing native PSGL-1 with actin cytoskeletal toxins inhibited adhesion In a dose-dependent way. PSGL-1 was associated with the actln cytoskeleton, and this interaction was greatly impaired in PSGL-1Δcytoexpressing cells. The PSGL-1 cytoplasmic domain interacted selectively with the ezrin/radixin/moesin (ERM) protein moesin, but not with other ERM proteins or several other cytoskeletal linker proteins. Pharmacologic disruption of interactions between moesin and F-actin in cells expressing PSGL-1 resulted In a dose-dependent inhibition of rolling on P-selectin. Thus, attachment of PSGL-1 to the leukocyte cortical cytoskeleton is essential for leukocyte rolling on P-selectin.
AB - P-selectin glycoproteln ligand-1 (PSGL-1) serves as the leukocyte ligand for P-selectin, and many of the structural features of its ectodomain required for interactions with P-selectin have been uncovered. In contrast, the function of the highly conserved PSGL-1 cytoplasmic domain has not been explored. Stable transfectants expressing similar levels of either wild-type PSGL-1 or truncated PSGL-1 in which only 4 cytoplasmic residues were retained (designated PSGL-1Δcyto), were analyzed. Transfectants expressing full-length PSGL-1 rolled well on P-selectin. In contrast, rolling was almost completely absent in cells transfected with PSGL-1Δcyto, even at low shear. Importantly, cells expressing truncated PSGL-1 were able to bind soluble P-selectin and to bind COS cells overexpressing P-selectin, demonstrating that the P-selectin binding site on the PSGL-1Δcyto transfectants was intact and was capable of recognizing P-selectin. Impaired rolling by PSGL-1Δcyto transfectants was not due to alterations in subcellular localization because both wild-type and truncated PSGL-1 had similar surface distributions on K562 transfectants. Treatment of cells expressing native PSGL-1 with actin cytoskeletal toxins inhibited adhesion In a dose-dependent way. PSGL-1 was associated with the actln cytoskeleton, and this interaction was greatly impaired in PSGL-1Δcytoexpressing cells. The PSGL-1 cytoplasmic domain interacted selectively with the ezrin/radixin/moesin (ERM) protein moesin, but not with other ERM proteins or several other cytoskeletal linker proteins. Pharmacologic disruption of interactions between moesin and F-actin in cells expressing PSGL-1 resulted In a dose-dependent inhibition of rolling on P-selectin. Thus, attachment of PSGL-1 to the leukocyte cortical cytoskeleton is essential for leukocyte rolling on P-selectin.
UR - http://www.scopus.com/inward/record.url?scp=0037097835&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0037097835&partnerID=8YFLogxK
U2 - 10.1182/blood.V99.12.4494
DO - 10.1182/blood.V99.12.4494
M3 - Article
C2 - 12036880
AN - SCOPUS:0037097835
SN - 0006-4971
VL - 99
SP - 4494
EP - 4502
JO - Blood
JF - Blood
IS - 12
ER -