Immunochemical characterisation of parathyroid hormone-related protein from tumour and non-tumour cells.
The molecular forms of parathyroid hormone-related protein (PTHRP) in conditioned media from the BEN human lung cancer cell line, rat parathyroid cells (PT-r) and human keratinocytes were studied by gel-filtration chromatography with assay of PTHRP by immunoassays and bioassay. Immunoreactivity (1-86 and 1-34) and bioactivity (1-34) in conditioned media eluted as a coincident major peak (approx. molecular mass 19-22 kDa) and there was evidence of amino-terminal species in the molecular mass range 10-16 kDa in BEN and keratinocyte media. Western blotting of PTHRP affinity purified by monoclonal antibodies directed at regions 1-34 or 37-67, identified a major species in all cell cytosols and media with an apparent molecular mass of 24-25 kDa, consistently slightly larger than recombinant PTHRP(1-141) (mobility of 21 kDa) which may represent an intact or native form of PTHRP. Additional amino-terminal species were identified in medium from keratinocytes (16 and 7 kDa), BEN cells (18 and 14 kDa) and PT-R cells (17 kDa), suggesting that processing occurs at the C-terminus and within the mid-region to form a range of amino-terminal fragments.
Emly
J F
JF
Wolfson Research Laboratories, Department of Clinical Chemistry, Queen Elizabeth Medical Centre, Birmingham, UK.
Ratcliffe
W A
WA
Green
E
E
Bowden
S J
SJ
Heath
D A
DA
Blight
A
A
Hughes
S
S
Ratcliffe
J G
JG
D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D006031:Glycosylation; D006801:Humans; D007120:Immunochemistry; D009363:Neoplasm Proteins / Q000737:chemistry* / Q000378:metabolism; D010281:Parathyroid Hormone / Q000378:metabolism*; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D051381:Rats; D014407:Tumor Cells, Cultured
D009363:Neoplasm Proteins; C470121:PTHLH protein, human; D010281:Parathyroid Hormone; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins