Abstract
RAFT1 (rapamycin and FKBP12 target 1; also called FRAP or mTOR) is a member of the ATM (ataxia telangiectasia mutated)–related family of proteins and functions as the in vivo mediator of the effects of the immunosuppressant rapamycin and as an important regulator of messenger RNA translation. In mammalian cells RAFT1 interacted with gephyrin, a widely expressed protein necessary for the clustering of glycine receptors at the cell membrane of neurons. RAFT1 mutants that could not associate with gephyrin failed to signal to downstream molecules, including the p70 ribosomal S6 kinase and the eIF-4E binding protein, 4E-BP1. The interaction with gephyrin ascribes a function to the large amino-terminal region of an ATM-related protein and reveals a role in signal transduction for the clustering protein gephyrin.
References
54
Referenced
161
- K. Savitsky et al. Science 268 1749 (1995)
-
K. O. Hartley et al. Cell 82 849 (1995)
(
10.1016/0092-8674(95)90482-4
) -
E. J. Brown et al. Nature 369 756 (1994)
(
10.1038/369756a0
) -
D. M. Sabatini et al. Cell 78 35 (1994)
(
10.3917/esp.1994.78.0035
) -
C. J. Sabers et al. J. Biol. Chem. 270 815 (1995);
(
10.1074/jbc.270.2.815
) -
Chiu M. I., Katz H., Berlin V., Proc. Natl. Acad. Sci. U.S.A. 91, 12574 (1994);
(
10.1073/pnas.91.26.12574
) / Proc. Natl. Acad. Sci. U.S.A. by Chiu M. I. (1994) - ; J. Kunz et al. Cell 73 585 (1993); R. Cafferkey et al. Mol. Cell. Biol. 13 6012 (1993); D. M. Morrow et al. Cell 82 831 (1995).
-
Jayaraman T., Marks A. R., J. Biol. Chem. 268, 25385 (1993);
(
10.1016/S0021-9258(19)74403-2
) / J. Biol. Chem. by Jayaraman T. (1993) - ; M. W. Albers et al. ibid. p. 22825;
-
Sehgal S. N., Baker H., Vezina C., J. Antibiot. (Tokyo) 28, 727 (1975);
(
10.7164/antibiotics.28.727
) / J. Antibiot. (Tokyo) by Sehgal S. N. (1975) 10.1126/science.1715094
-
Chung J., Kuo C. J., Crabtree G. R., Blenis J., Cell 69, 1227 (1992);
(
10.1016/0092-8674(92)90643-Q
) / Cell by Chung J. (1992) - ; C. J. Kuo et al. Nature 358 70 (1992); E. J. Brown et al. ibid. 377 441 (1995); L. Beretta et al. EMBO J. 15 658 (1996); S. R. von Manteuffel et al. Proc. Natl. Acad. Sci. U.S.A. 93 4076 (1996).
-
G. J. Brunn et al. Science 277 99 (1997).
(
10.1126/science.277.5322.99
) -
N. C. Barbet et al. Mol. Biol. Cell 7 25 (1996).
(
10.1091/mbc.7.1.25
) 10.1126/science.270.5233.50
-
P. E. Burnett et al. Proc. Natl. Acad. Sci. U.S.A. 95 1432 (1998).
(
10.1073/pnas.95.4.1432
) - The yeast reporter strain Y190 which contains the reporter genes lacZ and HIS3 downstream of binding sequences for GAL4 was sequentially transformed with pPC97 containing the cDNA for RAFT1(944–1338) and a rat hippocampal expression library in pPC86 [
-
Chevray P. M., Nathans D., Proc. Natl. Acad. Sci. U.S.A. 89, 5789 (1992);
(
10.1073/pnas.89.13.5789
) / Proc. Natl. Acad. Sci. U.S.A. by Chevray P. M. (1992) - ]. Screening of 6.5 × 10 6 clones yielded one His + -LacZ + colony. The rescued library plasmid encoded amino acids 209 to 685 of gephyrin. Truncations and mutations of RAFT1(944–1338) were made with polymerase chain reaction–based mutagenesis techniques.
-
P. Prior et al. Neuron 8 1161 (1992);
(
10.1016/0896-6273(92)90136-2
) -
Kirsch J., Wolters I., Triller A., Betz H., Nature 366, 745 (1993).
(
10.1038/366745a0
) / Nature by Kirsch J. (1993) -
Meyer G., Kirsch J., Betz H., Langosch D., Neuron 15, 563 (1995);
(
10.1016/0896-6273(95)90145-0
) / Neuron by Meyer G. (1995) -
Kirsch J., Kuhse J., Betz H., Mol. Cell. Neurosci. 6, 450 (1995).
(
10.1006/mcne.1995.1033
) / Mol. Cell. Neurosci. by Kirsch J. (1995) - GST and GST-gephyrin (residues 209 to 685) proteins were expressed in Escherichia coli BL21(DE3) and purified with glutathione-agarose [
-
Smith D. B., Johnson K. S., Gene 67, 31 (1988);
(
10.1016/0378-1119(88)90005-4
) / Gene by Smith D. B. (1988) - ]. Plates (10 cm in diameter) of 80% confluent HEK293 cells were lysed (300 μl per plate) in buffer A [50 mM Hepes-KOH (pH 7.4) 40 mM NaCl 0.5% Triton X-100 2 mM EDTA 1 mM phenylmethylsulfonyl fluoride aprotinin (5 mg/ml) antipain (1 mg/ml) leupeptin (1 mg/ml) chymostatin (6 mg/ml) and pepstatin A (0.7 mg/ml)] and 100 μl added to 5 μg of GST or GST-gephyrin bound to 20 μl of glutathione-agarose beads. After a 1-hour incubation on ice the beads were washed three times with buffer A containing 500 mM NaCl. Bound RAFT1 was eluted with 1.25× sample buffer and detected by immunoblotting with 782 antibody to RAFT1 (anti–782-RAFT1) (19).
- HEK293 cells plated on 10-cm dishes were transfected with the calcium phosphate precipitate method with myc-tagged RAFT1 variants (5 μg) and hemagglutinin (HA)–tagged gephyrin(209–685) in pRK5 (5 μg). After 24 to 36 hours cells were rinsed once with phosphate-buffered saline (PBS) and lysed in 1 ml of ice-cold buffer A (11) containing 1.5 mM Na 3 VO 4 50 mM NaF 10 mM sodium pyrophosphate and 10 mM sodium β-glycerophosphate. Immune complexes were prepared with 0.5 μl of rabbit antibody to HA (Babco) and 40 μl of protein A–Sepharose and washed three times with buffer A containing 500 mM NaCl. Bound proteins were eluted with 1.25× sample buffer and RAFT1 was detected by immunoblotting with 9E10 antibody to myc (Calbiochem).
- D. M. Sabatini and S. H. Snyder unpublished observations.
- In situ hybridization was done as described [
-
Blackshaw S., Snyder S. H., J. Neurosci. 17, 8074 (1997);
(
10.1523/JNEUROSCI.17-21-08074.1997
) / J. Neurosci. by Blackshaw S. (1997) - ] with sense or antisense digoxigenin-labeled RNA probes corresponding to amino acids 209 to 685 of gephyrin or 944 to 1338 of RAFT1 (13).
- Rat brain subcellular fractions were prepared as described [
-
Burnett P. E., et al., Proc. Natl. Acad. Sci. U.S.A. 95, 8351 (1998);
(
10.1073/pnas.95.14.8351
) / Proc. Natl. Acad. Sci. U.S.A. by Burnett P. E. (1998) - ]. The quality of the subcellular fractions was monitored by protein immunoblotting of 20 μg of each fraction with antibodies to mGluR1α (Pharmingen) PSD-95 (Santa Cruz) synaptophysin (Boehringer Mannheim) and FKBP12 [
-
Walensky L., et al., J. Cell Biol. 141, 143 (1998);
(
10.1083/jcb.141.1.143
) / J. Cell Biol. by Walensky L. (1998) - ]. The gephyrin [
-
Kawasaki B. T., Hoffman K. B., Yamamoto R. S., Bahr B. A., J. Neurosci. Res. 49, 381 (1997);
(
10.1002/(SICI)1097-4547(19970801)49:3<381::AID-JNR13>3.0.CO;2-2
) / J. Neurosci. Res. by Kawasaki B. T. (1997) - ] and RAFT1 antibodies (19) have been described.
-
Watters D., et al., Oncogene 14, 1911 (1997).
(
10.1038/sj.onc.1201037
) / Oncogene by Watters D. (1997) - Transfection of HA-p70 S6k in prk5 (100 ng) with >5 μg of any of several expression vectors encoding a variety of proteins results in less than 30% of the S6 kinase activity obtained when HA-p70 S6k (100 ng) is transfected with 10 μg of empty expression vector (13).
-
Steward O., Banker G. A., Trends Neurosci. 15, 180 (1992);
(
10.1016/0166-2236(92)90170-D
) / Trends Neurosci. by Steward O. (1992) -
Gao F. B., BioEssays 20, 70 (1998).
(
10.1002/(SICI)1521-1878(199801)20:1<70::AID-BIES10>3.0.CO;2-5
) / BioEssays by Gao F. B. (1998) -
D. M. Sabatini et al. J. Biol. Chem. 270 20875 (1995).
(
10.1074/jbc.270.36.20875
) - Single-letter abbreviations for amino acid residues are as follows: A Ala; C Cys; D Asp; E Glu; F Phe; G Gly; H His; I Ile; K Lys; L Leu; M Met; N Asn; P Pro; Q Gln; R Arg; S Ser; T Thr; V Val; W Trp; and Y Tyr.
- HeLa cells were fractionated [
-
Kruppa J., Sabatini D. D., J. Cell Biol. 74, 414 (1977);
(
10.1083/jcb.74.2.414
) / J. Cell Biol. by Kruppa J. (1977) - ] 50 μg of each fraction was resolved by SDS–polyacrylamide gel electrophoresis (SDS-PAGE) (6% gels) and RAFT1 was detected with antibody 782 to RAFT1 (19).
- HeLa cells grown on chamber slides were transfected with lipofectamine (Life Technologies) with expression vectors encoding mycGBD (residues 1010 to 1128 of RAFT1) (10 μg); mycRAFT1 (5 μg) and prk5 (5 μg); or mycRAFT1 (5 μg) and gephyrin P1 (5 μg) (9). After a 48-hour incubation the cells were processed for immunofluorescence [
-
Walensky L. D., Snyder S. H., J. Cell Biol. 130, 857 (1995);
(
10.1083/jcb.130.4.857
) / J. Cell Biol. by Walensky L. D. (1995) - ]. Antibodies 9E-10 to myc (2 μg/ml) or 782 to RAFT1 (5 μg/ml) (19) were used as the primary antibodies in an overnight incubation at 4°C.
- Expression constructs of p70 S6k 4E-BP1 and RAFT1 were prepared as described (7). HEK293 cells were transfected with HA-p70 S6k (100 ng) or HA–4E-BP1 (50 ng) alone or with 2 μg of each RAFT1 variant. The total amount of DNA was kept constant at 10 μg with empty pRK5. The cells were incubated overnight rinsed once with PBS and placed in medium without fetal bovine serum (FBS) for 30 to 48 hours. Cells were treated with 10 nM rapamycin (Calbiochem) for 30 min. Stimulation with 10% FBS was for 30 min. After treatments cells were rinsed once with PBS and lysed (12). Proteins were resolved by SDS-PAGE (8% gels for p70 S6k and 17% gels for 4E-BP1) and detected with immunoblotting.
- RAFT1 kinase assays were done as described (7). The addition to the assays of 1.5 μg of GST-gephyrin (11) did not affect RAFT1 autophosphorylation nor was gephyrin a RAFT1 substrate (13).
- We thank T. Morimoto for help with HeLa cell fractionation A. Lanahan and P. Worley for the rat hippocampal library and L. Walensky N. Cohen and J. Lawler for fruitful discussions. Supported by U.S. Public Health Service grant DA-00266 and Research Scientist Award DA-00074 to S.H.S. and training grant GM-07309 to D.M.S.
Dates
Type | When |
---|---|
Created | 23 years, 1 month ago (July 27, 2002, 5:37 a.m.) |
Deposited | 1 year, 7 months ago (Jan. 13, 2024, 4:09 a.m.) |
Indexed | 3 weeks ago (Aug. 7, 2025, 4:31 p.m.) |
Issued | 26 years, 3 months ago (May 14, 1999) |
Published | 26 years, 3 months ago (May 14, 1999) |
Published Print | 26 years, 3 months ago (May 14, 1999) |
@article{Sabatini_1999, title={Interaction of RAFT1 with Gephyrin Required for Rapamycin-Sensitive Signaling}, volume={284}, ISSN={1095-9203}, url={http://dx.doi.org/10.1126/science.284.5417.1161}, DOI={10.1126/science.284.5417.1161}, number={5417}, journal={Science}, publisher={American Association for the Advancement of Science (AAAS)}, author={Sabatini, David M. and Barrow, Roxanne K. and Blackshaw, Seth and Burnett, Patrick E. and Lai, Michael M. and Field, Michael E. and Bahr, Ben A. and Kirsch, Joachim and Betz, Heinrich and Snyder, Solomon H.}, year={1999}, month=may, pages={1161–1164} }