 Ning-Hui Cheng, Ph.D.
Instructor of Pediatrics
Baylor College of Medicine
ncheng@bcm.tmc.edu
Regulation of plant ion/metabolite transporters
My research interests center on studying redox regulation of insulin signaling
in nutrient metabolism with emphasis on metabolic disorders including type2
diabetes and obesity.
Redox regulation incorporates both transcriptional and post-translational mechanisms
to modulate gene expression and protein levels. Thiol group modification represents
one of redox control mechanisms in insulin action and signaling. There is growing
evidence that the glutaredoxin (Grx)/ glutathione (GSH)/ glutathione reductase
(GR) system, like the thioredoxin (Trx)/thioredoxin reductase (TR)/NADPH system, plays
an essential role in regulating cellular function. It will be important to understand
the mechanistic link between Grx-mediated redox signals and insulin signaling
pathways and the biochemical nature of those processes.
As an initial step towards this goal, we are currently investigating a novel
group of Grxs-monothiol Grxs, which were recently identified and isolated from
bacteria, fungi, plants, and animals including mammals. Recent studies from ours
and other laboratories indicate that monothiol Grxs contain a conserved PICOT-HD
(protein kinase C interacting cousin of thioredoxin homology domain)
and have a common function in regulating cellular processes in response to oxidative
stresses. By utilizing genetic, biochemical, and cell biology approaches, we
are going to determine a), the biochemical properties of those enzymes including
their enzymatic activities and substrate specificity; b), how these monothiol
Grxs, coupled with GSH and GR, regulate the targeted proteins in response to
cellular redox changes; and c), how the PICOT-HD integrates redox signals into
insulin/IGF mediated signaling. Elucidating the physiological role of PICOT will
lead to an understanding of the complexity of insulin resistance in the pathogenesis
of metabolic disorders, such as type2 diabetes and obesity.
Representative publications:
Cheng, N.-H.* (2008) AtGRX4, an Arabidopsis chloroplastic monothiol glutaredoxin,
is able to suppress yeast grx5 mutant phenotypes and respond to external stresses. FEBS Letters. (reversion) (*
Denotes Corresponding Author)
Koren’kov, V., Park, S., Cheng, N.-H., Sreevidya, C., Lachmansingh, J.,
Morris, J., Hirschi, K., Wagner, G.J. (2007) Enhanced Cd2+-selective root-tonoplast-transport
in tobacco expression Arabidopsis cation exchangers. Planta 255, 403-411,
2007.
Cheng, N-H.*, Liu, Z-J., Brock, A., Nelson, R.S., and Hirschi, K.D. AtGRXcp,
an Arabidopsis chloroplastic glutaredoxin is critical for protection against
protein oxidative damage. J. Biol. Chem. 281, 26280-26288, 2006.
Park S, Cheng N-H, Pittman JK, Yoo KS, Park J, Smith RH, Hirschi KD. Increased
calcium levels and prolonged shelf life in tomatoes expressing Arabidopsis H+/Ca2+
transporters. Plant Physiol. 139(3):1194-1206, 2005.
Cheng N-H, Pittman JK, Shigaki T, Lachmansingh J, LeClere S, Lahner B, Salt DE,
Hirschi KD. Functional association of Arabidopsis CAX1 and CAX3 is required for
normal growth and ion homeostasis. Plant Physiol. 138(4):2048-2060,
2005.
Pittman JK, Shigaki T, Marshall JL, Morris JL, Cheng N-H, Hirschi KD. Functional
and regulatory analysis of the Arabidopsis thaliana CAX2 cation transporter. Plant
Mol Biol. 56(6):959-971, 2004.
Ding X, Liu J, Cheng N-H, Folimonov A, Hou Y, Bao Y, Katagi C, Carter S, and
Nelson R (2004) The Tobacco mosaic virus 126-kDa protein associated with virus
replication and movement suppresses RNA silencing. Mol.Plant-Microbe Interact. 17,
583-592.
Yang S, Carter S, Cole A, Cheng N-H, and Nelson R (2004) A natural variant of
a host RNA-dependent RNA polymerase is associated with increased susceptibility
to viruses by Nicotiana benthamiana. Proc. Natl. Acad. Sci. USA 101,
6297-6302
Sze H, Padmanaban S, Cellier F, Honys D, Cheng N-H, Bock K, Conejero G, Li X,
Twell D, Ward JM, and Hirschi K (2004). Expression Patterns of a Novel AtCHX
Gene Family Highlight Potential Roles in Osmotic Adjustment and K1 Homeostasis
in Pollen Development. Plant Physiol. 136:2532-2547.
Pittman J, Cheng N-H, Shigaki T, Kunta M, Hirschi K (2004). Functional dependence
on calcineurin by variants of the Saccharomyces cerevisiae vacuolar Ca2+/H+ exchanger
Vcx1p. Molecular Microbiology 54 (4), 1104–1116.
Cheng N-H*, Liu J, Nelson S, Hirschi K (2004). Characterization of CXIP4, a novel Arabidopsis protein
that activates the H+/Ca2+ antiporter, CAX1. FEBS Letters. 559: 99-106.
Cheng N-H, Pittman J K, Zhu K, and Hirschi K (2004). The Protein Kinase SOS2
Activates the Arabidopsis H+/Ca2+ Antiporter CAX1 to Integrate Calcium Transport
and Salt Tolerance. J. Biol. Chem. 279: 2922-2926.
Cheng N-H and Hirschi K (2003). Cloning and Characterization of CXIP1, a Novel
PICOT Domain-containing Arabidopsis Protein That Associates with CAX1. J.
Biol. Chem. 278: 6503 - 6509.
Cheng N-H, Pittman J K, Barkla B, Shigaki T, and Hirschi K (2003). The
Arabidopsis cax1 Mutant Exhibits Impaired Ion Homeostasis, Development, and Hormonal
Responses and Reveals Interplay among Vacuolar Transporters. Plant Cell 2003
15: 347-364.
Cheng, N-H, Pittman, JK, Shigaki, T, and Hirschi, KD, (2002) Characterization
of CAX4, an Arabidopsis H+/Cation antiporter. Plant Phsiol. 128:1245-1254
Pittman, JK, Shigaki, T, Cheng, N-H, and Hirschi, KD, (2002) Mechanism of
N-terminal autoinhibition in the Arabidopsis Ca2+ /H+ antiporter CAX1. J Biol Chem 277, 26452-26459
Li XB, Cai L, Cheng,N-H, and Liu JW. (2002) Molecular characterization of
the cotton GhTUB1 gene that is preferentially expressed in fiber. Plant Physiol. 130(2):
666-74.
Shigaki, T, Cheng, N-H, Pittman, JK, and Hirschi, KD. (2001) Structural
determinants of Ca 2+ transport in the Arabidopsis H+/Ca2+ antiporter CAX1.
J Biol. Chem 276: 43152-43159
Cheng, N-H, Su, C-L, Carter, SA, and Nelson, RS. (2000). Vascular invasion routes and accumulation pattern of tobacco mosaic virus in Nicotiana;benthamiana; The
Plant Journal. 23: 349-363
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