Paul F. James

Associate Professor

278 Pearson Hall  (513) 529-3129
jamespf@miamioh.edu

Biographical Information

Paul James is a molecular physiologist who uses a synthesis of molecular biology, cell biology, biochemistry, and physiology to understand the specific in vivo functional roles of individual protein isoforms that transport ions across biological membranes.  Specifically, he is interested in using rats and mice (knockout and transgenic) as models to define the roles that isoforms of the Na,K-ATPase and the sodium hydrogen exchanger (NHE) play in male reproductive physiology.

The Na,K-ATPase transports sodium ions (Na+) out of the cell and potassium ions (K+) into the cell utilizing energy released during ATP hydrolysis thereby establishing electrochemical gradients across the cell membrane.  The NHEs maintain intracellular pH by transporting hydrogen ions (H+) out of the cell using the energy stored in the Na+ gradient established by the Na,K-ATPase.  Sperm contain two of the four known Na,K-ATPase alpha isoforms and at least four of the 12 identified NHE isoforms, two of which (alpha4 Na,K-ATPase and NHE10) have been shown to be critical for sperm motility and fertility.  The role that the other Na,K-ATPase and NHE isoforms play in sperm physiology is currently unresolved.  The focus in the James laboratory is directed towards 1) defining the distinct roles that individual Na,K-ATPase alpha and NHE isoforms play in regulating different aspects of sperm physiology (motility, capacitation, the acrosome reaction, etc.),  2) determining the specific functional interactions between these isoforms in sperm that allow regulation of intracellular pH, 3) identifying the cellular mechanisms that regulate the activity of these transporters in sperm, 4) investigating the role that the Na,K-ATPase alpha4 isoform and NHE10 play in human reproduction and reproductive dysfunction, and 5) examining the role that epigenetic mechanisms play in regulating the expression of the sperm-specific Na,K, ATPase and NHE isoform genes.

In addition to his work on the physiology of membrane transport proteins found in sperm, Dr. James is also collaborating in the design and testing of novel osteogenic and chondrogenic scaffold compositions/architectures for use in bone and cartilage tissue engineering.


Courses Taught

Introduction to Research in Biology (BIO 103)
Principles of Human Physiology (BIO 161)
Molecular Physiology (BIO 471/571)
Advanced Molecular Biology (BIO 605)
Advanced Seminar in Biology: Mechanisms of Migraines (BIO 710)
Advanced Seminar in Biology: RNAi in Animals (BIO 710)
Advanced Seminar in Biology: Epigenetics (BIO 710)
  

Recent Publications

  1. Akbarzadeh, R., Yousefi, A.M., James, P.F. Hierarchical Tissue Scaffold and Method of Fabrication Thereof, Submitted Provisional US Patent, 2013.
  2. Kaewsuya , P., Miller, J. D., Danielson, N. D., Sanjeevi, J., James, P.F. Comparison of N-Alkyl Acridine Orange Dyes as Fluorescence Probes for the Determination of Cardiolipin. Anal Chim Acta., 626(2):111-8, 2008.
  3. Hlivko, JT, Chakraborty, S, Hlivko, TJ, Sengupta, A, and James, PF. The Human Na,KATPase Alpha4 Isoform is a Ouabain-Sensitive Alpha Isoform that is Expressed in Sperm. Mol Repro Dev. 73(1):101-115, 2006.
  4. Woo, A.L., James, P.F., Lingrel, J.B. Roles of the Na,K-ATPase ?4 isoform and the Na+/H+ exchanger in sperm motility. (2002) Mol Repro Dev, 62(3):348-356, 2002.
  5. Woo. A,L,, James. P.F., Lingrel, J.B. Sperm motility is dependent on a unique isoform of the Na,K-ATPase.  J Biol Chem, 275: (27) 20693-20699, 2000.