Abstract
The Tim23 protein is an essential inner membrane (IM) component of the yeast mitochondrial protein import pathway. Tim23p does not carry an amino-terminal presequence; therefore, the targeting information resides within the mature protein. Tim23p is anchored in the IM via four transmembrane segments and has two positively charged loops facing the matrix. To identify the import signal for Tim23p, we have constructed several altered versions of the Tim23 protein and examined their function and import in yeast cells, as well as their import into isolated mitochondria. We replaced the positively charged amino acids in one or both loops with alanine residues and found that the positive charges are not required for import into mitochondria, but at least one positively charged loop is required for insertion into the IM. Furthermore, we find that the signal to target Tim23p to mitochondria is carried in at least two of the hydrophobic transmembrane segments. Our results suggest that Tim23p contains separate import signals: hydrophobic segments for targeting Tim23p to mitochondria, and positively charged loops for insertion into the IM. We therefore propose that Tim23p is imported into mitochondria in at least two distinct steps.
References
91
Referenced
61
10.1128/MCB.6.2.626
/ Mol. Cell. Biol. by Adrian G.S. (1986)10.1073/pnas.83.23.9011
/ Proc. Natl. Acad. Sci. USA by Allison D.S. (1986)10.1002/j.1460-2075.1985.tb03941.x
/ EMBO J. by Aquila H. (1985)10.1016/S0092-8674(00)81320-3
/ Cell by Bauer M. (1996)10.1111/j.1432-1033.1974.tb03599.x
/ Eur. J. Biochem. by Bonner W.M. (1974)10.1002/(SICI)1097-0061(19980130)14:2<115::AID-YEA204>3.0.CO;2-2
/ Yeast by Brachmann C.B. (1998)10.1074/jbc.272.33.20730
/ J. Biol. Chem. by Brix J. (1997)10.1016/0092-8674(87)90541-1
/ Cell by Chen W.J. (1987){'key': 'B9', 'first-page': '13028', 'volume': '257', 'author': 'Daum G.', 'year': '1982', 'journal-title': 'J. Cell Biol.'}
/ J. Cell Biol. by Daum G. (1982)10.1016/0014-5793(93)80921-G
/ FEBS Lett. by Dekker P. (1993)10.1002/j.1460-2075.1988.tb02923.x
/ EMBO J. by Eilers M. (1988)10.1002/j.1460-2075.1987.tb04860.x
/ EMBO J. by Eilers M. (1987)10.1083/jcb.122.5.1003
/ J. Cell Biol. by Emtage J.L.T. (1993)10.1128/MCB.8.5.2159
/ Mol. Cell. Biol. by Field J. (1988)10.1002/j.1460-2075.1996.tb00380.x
/ EMBO J. by Fölsch H. (1996)10.1016/S0021-9258(18)77287-6
/ J. Biol. Chem. by Gawaz M. (1990)10.1016/0092-8674(95)90444-1
/ Cell by Glick B.S. (1995)10.1083/jcb.129.1.25
/ J. Cell Biol. by Gratzer S. (1995)10.1002/j.1460-2075.1994.tb06844.x
/ EMBO J. by Hachiya N. (1994)10.1038/376705a0
/ Nature by Hachiya N. (1995)10.1016/S0076-6879(83)96017-2
/ Methods Enzymol. by Haid A. (1983)10.1093/emboj/16.9.2217
/ EMBO J. by Herrmann J.M. (1997)10.1002/j.1460-2075.1990.tb07517.x
/ EMBO J. by Hines V. (1990)10.1023/A:1022470303365
/ J. Bioenerg. Biomembr. by Jensen R.E. (1997)10.1002/j.1460-2075.1988.tb03272.x
/ EMBO J. by Jensen R.E. (1988)10.1093/emboj/17.6.1569
/ EMBO J. by Káldi K. (1998)10.1038/348137a0
/ Nature by Kang P.J. (1990)10.1083/jcb.139.7.1663
/ J. Cell Biol. by Kerscher O. (1997)10.1016/0092-8674(93)80050-O
/ Cell by Kiebler M. (1993)10.1038/348610a0
/ Nature by Kiebler M. (1990)10.1111/j.1432-1033.1996.00856.x
/ Eur. J. Biochem. by Klaus C. (1996)10.1126/science.279.5349.369
/ Science by Koehler C.M. (1998)10.1093/emboj/16.14.4267
/ EMBO J. by Komiya T. (1997)10.1002/j.1460-2075.1996.tb00370.x
/ EMBO J. by Komiya T. (1996)10.1074/jbc.273.26.16374
/ J. Biol. Chem. by Kübrich M. (1998)10.1038/227680a0
/ Nature by Laemmli U.K. (1970)10.1016/S0021-9258(18)68111-6
/ J. Biol. Chem. by Lawson J.E. (1988)10.1016/S0021-9258(18)77286-4
/ J. Biol. Chem. by Lawson J.E. (1990)10.1083/jcb.107.2.503
/ J. Cell Biol. by Liu X.Q. (1988)10.1016/S0021-9258(19)40186-5
/ J. Biol. Chem. by Liu X.Q. (1990)10.1083/jcb.137.2.377
/ J. Cell Biol. by Lohret T.A. (1997)10.1002/j.1460-2075.1992.tb05446.x
/ EMBO J. by Maarse A.C. (1992)10.1016/0014-5793(94)00669-5
/ FEBS Lett. by Maarse A.C. (1994)10.1111/j.1432-1033.1990.tb19260.x
/ Eur. J. Biochem. by Mahlke K. (1990)10.1002/j.1460-2075.1995.tb00094.x
/ EMBO J. by Mayer A. (1995)10.1016/S0021-9258(19)81092-X
/ J. Biol. Chem. by McAda P.C. (1982)10.1083/jcb.112.5.833
/ J. Cell Biol. by Miller B.R. (1991)10.1083/jcb.121.5.1021
/ J. Cell Biol. by Miller B.R. (1993)10.1016/0014-5793(92)81345-M
/ FEBS Lett. by Moczko M. (1992)10.1073/pnas.80.16.4949
/ Proc. Natl. Acad. Sci. USA by Niman H.L. (1983)10.1007/BF01108406
/ J Bioenerg. Biomembr. by Palmieri F. (1993)10.1016/0968-0004(94)90113-9
/ Trends Biochem. Sci. by Pfanner N. (1994)10.1016/S0021-9258(18)48101-X
/ J. Biol. Chem. by Pfanner N. (1987)10.1016/S0960-9822(06)00048-0
/ Curr. Biol. by Pfanner N. (1997)10.1002/j.1460-2075.1987.tb02668.x
/ EMBO J. by Pfanner N. (1987)10.1002/j.1460-2075.1985.tb04009.x
/ EMBO J. by Pfanner N. (1985)10.1016/S0021-9258(18)47598-9
/ J. Biol. Chem. by Pfanner N. (1987)10.1016/0092-8674(87)90619-2
/ Cell by Pfanner N. (1987)10.1002/j.1460-2075.1988.tb03225.x
/ EMBO J. by Pollock R.A. (1988)10.1073/pnas.89.2.608
/ Proc. Natl. Acad. Sci. USA by Roise D. (1992)10.1002/j.1460-2075.1986.tb04363.x
/ EMBO J. by Roise D. (1986)10.1002/j.1460-2075.1988.tb02859.x
/ EMBO J. by Roise D. (1988)10.1002/j.1460-2075.1987.tb02377.x
/ EMBO J. by Runswick M.J. (1987)10.1016/S0021-9258(20)80441-4
/ J. Biol. Chem. by Ryan K.R. (1993)10.1128/MCB.18.1.178
/ Mol. Cell. Biol. by Ryan K.R. (1998)10.1091/mbc.5.5.529
10.1126/science.2999980
/ Science by Saiki R.K. (1985)10.1126/science.271.5255.1519
/ Science by Schatz G. (1996)10.1073/pnas.89.24.11930
/ Proc. Natl. Acad. Sci. USA by Scherer P.E. (1992)10.1007/BF00340712
/ Curr. Genet. by Schiestl R.H. (1989)10.1111/j.1432-1033.1982.tb06657.x
/ Eur. J. Biochem. by Schleyer M. (1982)10.1016/S0021-9258(17)32657-1
/ J. Biol. Chem. by Schlossmann J. (1994)10.1093/genetics/49.1.39
/ Genetics by Sherman F. (1964)10.1016/0076-6879(91)94023-6
/ Methods Enzymol. by Sikorski R. (1991)10.1093/genetics/122.1.19
/ Genetics by Sikorski R. (1989)10.1038/384582a0
/ Nature by Sirrenberg C. (1996)10.1038/36136
/ Nature by Sirrenberg C. (1998)10.1016/S0021-9258(18)68711-3
/ J. Biol. Chem. by Smagula C. (1988)10.1002/jcb.240360402
/ J. Cell. Biochem. by Smagula C.S. (1988)10.1016/0092-8674(89)90762-9
/ Cell by Söllner T. (1989)10.1016/0092-8674(90)90244-9
/ Cell by Söllner T. (1990)10.1038/355084a0
/ Nature by Söllner T. (1992)10.1111/j.1432-1033.1994.tb18593.x
/ Eur. J. Biochem. by Stuart R.A. (1994)10.1016/S0968-0004(96)10035-9
/ Trends Biochem. Sci. by Stuart R.A. (1996)10.1247/csf.21.403
/ Cell Struct. Funct. by Stuart R.A. (1996)10.1074/jbc.270.50.29848
/ J. Biol. Chem. by von Ahsen O. (1995)10.1091/mbc.5.4.465
10.1002/j.1460-2075.1988.tb02961.x
/ EMBO J. by Witte C. (1988)10.1002/j.1460-2075.1985.tb03893.x
/ EMBO J. by Yaffe M.P. (1985)10.1002/j.1460-2075.1988.tb03271.x
/ EMBO J. by Yang M. (1988)10.1111/j.1432-1033.1991.tb16029.x
/ Eur. J. Biochem. by Zara V. (1991)
Dates
Type | When |
---|---|
Created | 12 years, 2 months ago (July 2, 2013, 7:16 p.m.) |
Deposited | 3 years, 6 months ago (Feb. 26, 2022, 9:37 p.m.) |
Indexed | 2 months, 1 week ago (June 27, 2025, 6:37 a.m.) |
Issued | 27 years ago (Sept. 1, 1998) |
Published | 27 years ago (Sept. 1, 1998) |
Published Print | 27 years ago (Sept. 1, 1998) |
@article{Davis_1998, title={Tim23p Contains Separate and Distinct Signals for Targeting to Mitochondria and Insertion into the Inner Membrane}, volume={9}, ISSN={1939-4586}, url={http://dx.doi.org/10.1091/mbc.9.9.2577}, DOI={10.1091/mbc.9.9.2577}, number={9}, journal={Molecular Biology of the Cell}, publisher={American Society for Cell Biology (ASCB)}, author={Davis, Alison J. and Ryan, Kathleen R. and Jensen, Robert E.}, editor={Fox, Thomas D.}, year={1998}, month=sep, pages={2577–2593} }