Identification of receptors for prothymosin alpha on human lymphocytes.
Prothymosin alpha (ProTalpha) is a highly conserved and widely distributed protein whose physiological functions remain elusive. In previous work we identified high and low affinity-binding sites for ProTalpha in lymphoid cells. Here we demonstrate, by affinity cross-linking and affinity chromatography, the existence of three binding partners (31, 29, and 19 kDa) for ProTalpha in the membrane of PHA-activated lymphoblasts. These surface molecules possess the expected affinity and specificity for a ProTalpha receptor. Examination of the expression of this complex of molecules by flow cytometry reveals that they bind ProTalpha in a specific and saturable way. In addition, the distribution of the receptor on the cell surface was studied by fluorescence microscopy; a cap-like structure at one of the poles of the cells was identified. These results represent a new and promising approach in the research on ProTalpha, opening the way toward the understanding of the molecular mechanism of action of this protein.
Piñeiro
A
A
Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Santiago de Compostela, Spain.
Begoña Bugia
M
M
Pilar Arias
M
M
Cordero
O J
OJ
Nogueira
M
M
D001710:Biotin / Q000737:chemistry; D002846:Chromatography, Affinity; D003432:Cross-Linking Reagents / Q000737:chemistry; D005434:Flow Cytometry; D006801:Humans; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D010835:Phytohemagglutinins / Q000494:pharmacology; D011498:Protein Precursors / Q000737:chemistry / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D013947:Thymosin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism*
D003432:Cross-Linking Reagents; D010835:Phytohemagglutinins; D011498:Protein Precursors; D011956:Receptors, Cell Surface; C040782:prothymosin alpha; D013947:Thymosin; D001710:Biotin