Jean Jiang, PhD, Professor
Intercellular communication and intracellular signaling by gap junctions and hemichannels, and connexins in growth control, cell cycle and cell differentiation
Cells connect and communicate via an information superhighway named gap junctions. Gap junctions are clusters of transmembrane channels that connect the cytoplasm of adjacent cells. These channels are formed by a family of proteins called connexins. Gap junction channels permit small metabolites, ions, and second messengers to pass from cell to cell. Cells like lens fibers within the interior of the vertebrate eye lens have neither a blood supply nor organelles. Thus, lens survival and homeostasis are uniquely dependent upon intercellular communication via gap junctions with the cells localized at the lens surface. For cells like bone osteocytes, signals generated by mechanical loading can be transmitted extensively at high speed through gap junction channels. Therefore, gap junctions provide the critical means for cell survival and for physiological regulation of cellular functions. In addition to forming gap junctions, connexins are recently shown to form hemichannels, un-apposed halves of gap junction channels. Hemichannels mediate the passage of biological molecules, especially for cells under stress conditions.
Our current research interests are:
1). To determine the gap junction or hemichannel-dependent and independent roles of connexins in cell growth, cell cycle control and lens epithelial-fiber differentiation and lens development; regulatory mechanism of channels by aquoporin 0.
2). To explore the molecular mechanism and functional significance of gap junctions and hemichannels in transmitting the signals generated by mechanical stress for mineralized tissue formation and remodeling using in vitro cell models and in vivo transgenic mice.
Structure-function of amino acid transporters and their roles in neurodegeneration and oxidative stress.
Cellular metabolic needs are fulfilled by import of amino acids across the plasma membrane via specialized transporter proteins. We have identified a new family of amino acid transporters, named as system N/A amino acid transporters (SNATs).
Our current research interests are:
1). To characterize the structure-function relationship of identified transporters, and the characterization of post-translational modifications.
2). To investigate the biological roles of the amino acid transporters in neurological functions and oxidative stress using gene deficient mouse model generated by our
- Developmental truncations of connexin 50 by caspases adaptively regulate gap junctions/hemichannels and protect cells against UV radiation.
Wang, K., Gu, S., Yin, X., Weintraub, S.T., Hua, Z. and Jiang, J.X.
J. Biol. Chem.: 2012-05-14; 287(); 15786-15797 Epub: 2012-03-14.
- Mechanical stress-activated integrin α5β1 induces opening of connexin 43 hemichannels.
Batra N, Burra S, Siller-Jackson AJ, Gu S, Xia X, Weber GF, DeSimone D, Bonewald LF, Lafer EM, Sprague E, Schwartz MA, Jiang JX
Proc Natl Acad Sci U S A: 2012-02-28; 109(9); 3359-64 Epub: 2012-02-13.
PMID: 22331870   LINK:
- Membrane topological structure of SNAT4 neutral amino acid transporter
Shi, Q., Padmanabhan, R., Villegas, C.J., Gu, S., and Jiang, J.X.
J. Biol. Chem.: 2011-11-04; 286(); 38086-38094 Epub: 2011-09-14.
- Aquaporin 0 enhances gap junction coupling via its cell adhesion function and interaction with connexin 50.
Liu J, Xu J, Gu S, Nicholson BJ, Jiang JX
J Cell Sci: 2011-01-15; 124(Pt 2); 198-206 Epub: 2010-12-20.
PMID: 21172802   LINK:
- Dendritic process of osteocytes is a mechanotransducer that induces the opening of hemichannels
Burra, S., Nicolella. D.P., Francis, W.L., Freitas, C.J., Mueschke, N.J., Poole, C., and Jiang, J.X.
Proc. Natl. Acad. Sci.: 2010-08-03; 107(); 13648-13653 Epub: 2010-07-19.
Complete Publication Listing