title: Tyrosine sulfation of native mouse Psgl-1 is required for optimal leukocyte rolling on P-selectin in vivo.
abstract: BACKGROUND
  We recently demonstrated that tyrosine sulfation is an important contributor to monocyte recruitment and retention in a mouse model of atherosclerosis. P-selectin glycoprotein ligand-1 (Psgl-1) is tyrosine-sulfated in mouse monocyte/macrophages and its interaction with P-selectin is important in monocyte recruitment in atherosclerosis. However, whether tyrosine sulfation is required for the P-selectin binding function of mouse Psgl-1 is unknown. Here we test the function of native Psgl-1 expressed in leukocytes lacking endogenous tyrosylprotein sulfotransferase (TPST) activity.
  
  
  RESULTS
  Psgl-1 function was assessed by examining P-selectin dependent leukocyte rolling in post-capillary venules of C57BL6 mice transplanted with hematopoietic progenitors from wild type (WT → B6) or Tpst1;Tpst2 double knockout mice (Tpst DKO → B6) which lack TPST activity. We observed that rolling flux fractions were lower and leukocyte rolling velocities were higher in Tpst DKO → B6 venules compared to WT → B6 venules. Similar results were observed on immobilized P-selectin in vitro. Finally, Tpst DKO leukocytes bound less P-selectin than wild type leukocytes despite equivalent surface expression of Psgl-1.
  
  
  CONCLUSIONS
  These findings provide direct and convincing evidence that tyrosine sulfation is required for optimal function of mouse Psgl-1 in vivo and suggests that tyrosine sulfation of Psgl-1 contributes to the development of atherosclerosis.
authors.affiliation: Oklahoma Medical Research Foundation, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America. Andrew-Westmuckett@omrf.org
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Westmuckett
authors.forename: Kelly M
authors.initials: KM
authors.lastname: Thacker
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Moore
mesh_terms: D000818:Animals; D019556:COS Cells; D002196:Capillaries / Q000378:metabolism; D002522:Chlorocebus aethiops; D005260:Female; D005434:Flow Cytometry; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods; D036904:Leukocyte Rolling; D007962:Leukocytes / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D019007:P-Selectin / Q000378:metabolism*; D011485:Protein Binding; D013431:Sulfates / Q000378:metabolism; D015238:Sulfotransferases / Q000235:genetics / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism*; D014699:Venules / Q000378:metabolism
chemical_list: D008562:Membrane Glycoproteins; D019007:P-Selectin; C084882:P-selectin ligand protein; D013431:Sulfates; D014443:Tyrosine; D015238:Sulfotransferases; C529648:TPST2 protein, mouse; C039079:protein-tyrosine sulfotransferase