| Autor: |
Klinz, Franz-Josef, Seifert, Roland, Schwaner, Ingo, Gausepohl, Heinrich, Frank, Rainer, Schultz, Günter |
| Předmět: |
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| Zdroj: |
European Journal of Biochemistry; 7/1/92, Vol. 207 Issue 1, p207-213, 7p |
| Abstrakt: |
Specific antibodies against raplA and raplB small GTP-binding proteins were generated by immunization of rabbits with peptides derived from the C-terminus of the processed proteins. Immunoblot analysis of membranes from several mammalian cell lines and human thrombocytes with afffinity-purified antibodies against raplA or raplB demonstrated the presence of multiple immunoreactive proteins in the 22- 23 kDa range, although at strongly varying levels. Whereas both proteins were present in substantial amounts in membranes from myelocytic HL-60, K-562 and HEL cells, they were hardly detectable in membranes from lymphoma U-937 and S49.1 cyc- cells. Membranes from human thrombocytes and 3T3-Swiss Albino fibroblasts showed strong raplB immunoreactivity, whereas raplA protein was present in much lower amounts. In the cytosol of HL60 cells, only small amounts of raplA and rapl B proteins were detected, unless the cells were treated with lovastatin, an inhibitor of hydroxymethylglutaryl-coenzyme A reductase, suggesting that both proteins are isoprenylated. By comparison with recombinant proteins, the ratio of rapl ARas proteins in membranes from HL-60 cells was estimated to be about 4:1. An antiserum directed against the C terminus of rap2 reacted strongly with recombinant rap2, but not with membranes from tested mammalian cells. In conclusion, raplA and raplB proteins are distributed differentially among membranes from various mammalian cell types and are isoprenylated in HL-60 cells. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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