Expression of a 70-kDa immunoreactive form of bile salt-dependent lipase by human pancreatic tumoral mia PaCa-2 cells.
This work describes the characterization of an immunoreactive form of bile salt-dependent lipase (BSDL) expressed by the human pancreatic tumoral Mia PaCa-2 cell line. This BSDL-related protein, which has an M(r) of 70 kDa, is enzymatically active and poorly secreted. Furthermore, a protein with the same electrophoretic migration can also be immunoprecipitated with polyclonal antibodies specific for the human pancreatic BSDL after in vitro translation of RNA isolated from Mia PaCa-2 cells. These data indicated that this BSDL-related protein might be poorly, or not, glycosylated. Reverse transcription and amplification of RNA extracted from Mia PaCa-2 cells using primers able to specifically amplify the full-length mRNA of the human BSDL resulted in a detectable 1.8-kb cDNA product, shorter than that of BSDL (2.2 kb). The sequence of this transcript corresponds to the mRNA sequence that codes for the mature human pancreatic BSDL. However, a deletion of 330 bp is located within the 3'-domain of this cDNA. Therefore data allowed us to conclude that the 70-kDa BSDL-related protein is a 612 amino acid length protein and represents a truncated form of BSDL. The deletion of 110 amino acids occurs in the C-terminal region of the protein, which encompasses 6 tandemly repeated sequences instead of the 16 normally present in the sequence of BSDL. Because feto-acinar pancreatic protein (FAPP), which is the oncofetal counterpart of BSDL, is a C-terminally truncated isoform of BSDL, it is suggested that the 70-kDa BSDL-related protein expressed in MiaPaCa-2 cells could be representative of the protein moiety of FAPP.
Pasqualini
E
E
Faculté de Médecine-Timone, INSERM U260, 27 Blvd. Jean Moulin, Marseille Cedex 05, 13385, France.
Caillol
N
N
Panicot
L
L
Valette
A
A
Lombardo
D
D
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics; D002474:Cell-Free System / Q000378:metabolism; D006023:Glycoproteins / Q000235:genetics; D006031:Glycosylation; D006801:Humans; D007164:Immunosorbents; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D008049:Lipase; D008969:Molecular Sequence Data; D010179:Pancreas / Q000378:metabolism; D010190:Pancreatic Neoplasms / Q000201:enzymology* / Q000473:pathology; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D002787:Sterol Esterase / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D020080:Tandem Repeat Sequences / Q000235:genetics; D014407:Tumor Cells, Cultured
D002352:Carrier Proteins; D006023:Glycoproteins; D007164:Immunosorbents; D007527:Isoenzymes; D012333:RNA, Messenger; C054784:bile salt-stimulated lipase; D002787:Sterol Esterase; C054621:CEL protein, human; D008049:Lipase