Human CD69 associates with an N-terminal fragment of calreticulin at the cell surface.
CD69 is thought to be a pluripotent signaling molecule expressed on the surface of a number of activated leukocytes including B, T, and NK cells, monocytes, neutrophils, and platelets. While some advances have been made regarding the mechanisms by which CD69 may participate in such diverse functions as cell aggregation, cellular cytotoxicity, and release of cytokines and inflammatory mediators, the most proximal links of signal initiation have not been identified. Our study has identified, by immunoprecipitation and direct protein sequencing (LC/MS/MS), binding of CD69 to an N-terminal protein fragment of calreticulin expressed on the cell surface of human PBMCs. Given the recently identified roles calreticulin plays in cell adhesion and angiogensis, the identification of CD69 binding directly to calreticulin may provide insights into mechanism(s) by which CD69 or other CD69 family members, i.e., LLT1 and AICL participates in such diverse functions.
Vance
Barbara A
BA
National Institutes of Health, National Cancer Institute, Center for Cancer Research, Experimental Transplantation and Immunology Branch, Bethesda, MD 20892-1306, USA. vanceb@mail.med.upenn.edu
Harley
Patricia H
PH
Backlund
Peter S
PS
Ward
Yvona
Y
Phelps
Tracy L
TL
Gress
Ronald E
RE
D000595:Amino Acid Sequence; D015703:Antigens, CD / Q000737:chemistry / Q000378:metabolism*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D037282:Calreticulin / Q000737:chemistry / Q000378:metabolism*; D002450:Cell Communication / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D006801:Humans; D037181:Lectins, C-Type; D007963:Leukocytes, Mononuclear / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D025941:Protein Interaction Mapping / Q000379:methods*; D000099192:CD69 Antigens
D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D037282:Calreticulin; D037181:Lectins, C-Type; D000099192:CD69 Antigens