Jill L. Johnson, Ph.D.
Campus Locations: Moscow
With UI Since 2002
PHD Biochemistry and Molecular Biology Mayo Graduate School, 1994
BS Cellular and Molecular Biology,University of Michigan, 1988
My research focuses on the role of molecular chaperones in the cell. Molecular chaperones are highly conserved proteins found in every cellular compartment of every organism studied. In general, chaperones prevent inappropriate interactions that may result in proteins becoming unfolded, and they function both during normal cellular processes, such as protein synthesis, and also during times of environmental stress, such as heat shock.
In particular, I study the function of a chaperone called Hsp90 (90 kDa heat shock protein). Hsp90 is an essential chaperone that is required for the activity of a number of 'client' proteins involved in signal transduction pathways and cell cycle regulation, such as steroid hormone receptors and oncogenic tyrosine kinases. Hsp90 functions with at least 5 other proteins in an ordered pathway of interaction that results in the proper folding and activity of the client protein. I use genetic and biochemical studies with the yeast, Saccharomyces cerevisiae, in an attempt to understand what all these co-chaperones are doing and why so many of them are required. My current work focuses on the role of two of these co-chaperones, Hsp40 and Hsp70, which interact with client proteins before Hsp90. I am interested in determining what structural features of a client protein promote interaction with Hsp40 and Hsp70, as well as investigating how Hsp90 is recruited to the pathway.
- Bao, X, Johnson JL and Rao, H. (2015) Rad25 is targeted for degradation by the Ubc4-Ufd4 pathway. Journal Biological Chemistry. 290(13):8606-8612.<.li>
- Tenge VR, Zuehlke AD, Shrestha N, and Johnson JL. (2015) The Hsp90 co-chaperones Cpr6, Cpr7 and Cns1 interact with the intact ribosome. Eukaryotic Cell. 14(1):55-63.
- Johnson JL, Zuehlke AD, Tenge VR and Langworthy JC. (2014) Mutation of essential Hsp90 co-chaperones SGT1 or CNS1 renders yeast hypersensitive to overexpression of other co-chaperones. Current Genetics. 60(4):265-65.
- Paul A, Garcia YA, Zierer B, Patwardhan C, Gutierrez, O Hildenbrand Z, Harris DC, Balsiger HA, Sivils JC, Johnson JL, Buchner J, Chadli A and Cox MB (2014). The Cochaperone SGTA (Small Glutamine-Rich Tetratricopeptide Repeat-Containing Protein Alpha) Demonstrates Regulatory Specificity for the Androgen, Glucocorticoid and Progesterone Receptors. Journal of Biological Chemistry. 289: 15297-15308.
- Tenge, V, Knowles J. and Johnson JL (2014). The ribosomal biogenesis protein Utp21 interacts with Hsp90 and has differing requirements for Hsp90-associated proteins. PLOS One 9(3):e92569. Zuehlke AD, Wren N, Tenge V and Johnson JL. (2013) Interaction of Hsp90 and the co- chaperone Cpr6 with Ura2, a bifunctional enzyme required for pyrimidine biosynthesis. Journal of Biological Chemistry. In press.
- Chiosis G, Dickey CA and Johnson JL (2013). A global view of Hsp90 functions. Meeting report. Nature Structural and Molecular Biology. 20 (1): 1-4.
- Zuehlke AD, and Johnson JL. (2012). Chaperoning the chaperone: a role for the co-chaperone Cpr7 in modulating Hsp90 function in Saccharomyces cerevisiae. Genetics. 191:805-814.
- Flom GA, Langner E and Johnson JL. (2012) Identification of an Hsp90 mutation that selectively disrupts cAMP/PKA signaling in Saccharomyces cerevisiae. Current Genetics. 58(3):149-63.
- Johnson J.L. (2012) Evolution and function of diverse Hsp90 homologs and cochaperone proteins. Biochim. Biophys Acta. 1823(3):607-13.
- Cox MB and Johnson JL. (2011) The role of p23, Hop, immunophilins and other co-chaperones inregulating Hsp90 function. Methods and Protocols Series: Methods in Molecular Biology, Molecular Chaperones Vol. 787. Calderwood, Stuart K.; Prince, Thomas L. (Eds.), 2011.
- Nillegoda NB, Theodoraki MA, Mandal AK, Mayo KJ, Ren HY, Sultana R, Wu K, Johnson J, Cyr D and Caplan AJ. (2010) Ubr1 and Ubr2 function in a quality control pathway for degradation of unfolded cytosolic proteins. Mol. Biol. Cell. 21:2102-16.
- Zuehlke A and Johnson JL (2010). Hsp90 and co-chaperones twist the functions of diverse client proteins. Biopolymers. 93 (3):211-217.
- Footz TK, Johnson JL, Dubois S, Boivin N, Raymond V and Walter MA. (2009) Glaucoma-associated WDR36 variants encode functional defects in a yeast model system. Hum Mol Genet 18:1276-1287.
- Johnson JL and Brown C. (2009) Plasticity of the Hsp90 molecular chaperone machine in divergenteukaryotic organisms. Cell Stress and Chaperones.14:83-94.
- Flom GA, Lemieszek M, Fortunato EA and Johnson JL. (2008) Farnesylation of Ydj1 is required for the in vivo interaction with Hsp90 client proteins. Molecular Biology of the Cell. 19:5249-5248.
- Flom G, Behal RH, Rosen L, Cole DG and Johnson JL. (2007) Definition of the minimal fragments of Sti1 required for dimerization, interaction with Hsp70 and Hsp90 and in vivo functions. Biochem. J. 404, 159-167.