PINFEN YANG
Associate Professor

B.S., 1986, National Taiwan University, Taipei
M.S., 1988, Purdue University
Ph.D., 1993, Case Western Reserve University
Postdoctoral Fellow, Emory University
Ph. D. Case Western Reserve University 1988-1993
Postdoctoral Fellow, Emory University, 1994-2001

WLS 312
(414) 288-5663
email: pinfen.yang@marquette.edu

Click on the Lab Webpage for more information about Dr. Yang's research program, coursework, and a complete list of publications.

Signal Transduction and Control of Molecular Motors

The long-term goal of my laboratory is to understand how cilia and flagella beat. These eukaryotic organelles are powerful biological machines beating with extremely high frequency and sophisticated waveform to propel cell body or the surrounding fluid. The vigorous movement is essential for the function of vital organs.

The beating is powered by the dynein motors anchored to the 9+2 microtubule-based axoneme. Importantly, the motors are tightly regulated to allow these organelles to beat with particular patterns and to change the beating. Diverse evidence suggests that a control system within the 9 outer doublets, including radial spokes and central pair, play a crucial role in controlling the dynein motors. In particular, radial spoke appears to operate as a mechanochemical transducer and via a network of second messenger-dependent and independent phosphoenzymes.

To test this hypothesis, my lab have been using green algae, Chlamydomonas, as a model system, taking advantage of numerous motility mutants, genomics and EST database and various molecular cellular techniques, such as proteomics, high speed digital microscopy, fluorescent microscopy, electron microscopy, molecular cloning, RNAi, mutagenesis and transformation rescue of mutant strains. For example, my lab has taken proteomic approach to identify and clone individual radial spoke proteins systematically. We discovered radial spokes contain molecular chaperones possibly involved in the assembly of this evolutionally conserved macromolecular complex and several novel enzymes and regulatory proteins with the functional motifs that usually are involved in calcium, and cyclic nucleotides signaling. The current focus is to test the molecular model depicted underneath. The DnaJ chaperone was depleted by RNAi and the mutants strains display irregular stalling of stroke initiation and bend propagation, indicating defective timing of coordinated activation of dynein motors (compare high speed video microscopy of wild type and DnaJ- cells).  Thus, this study indicates that DnaJ plays an important role in radial spokes that is integral component of a feedback mechanism in coordinating dynein activation for flagellar oscillatory beating.  Experiments are underway to test the molecules involved in the proposed mechanical feedback and chemical signaling.

Selected Publications

C. Yang and P. Yang. 2006. The flagellar motility of Chlamydomonas pf25 mutant lacking an AKAP binding protein is overtly sensitive to medium conditions.  Mol. Biol. Cell. 17:227-238.

P. Yang, D. R. Diener, C. Yang, T. Kohno, G. J. Pazour, J. M. Dienes, N. Agrin, S. M. King, W. S. Sale, R. Kamiya, J. L. Rosenbaum, and G. B. Witman.  2006. Radial Spoke Proteins of Chlamydomonas Flagella. J. Cell Sci.  119:1165-1174.

Yang, C., Compton, M. M. and Yang, P.  2005. Dimeric novel HSP40 is incorporated into the radial spoke complex during the assembly process in flagella. Mol. Biol. Cell. 16:637-48.

Smith, E.F. and P. Yang.  2004.  The radial spokes and central apparatus: mechano-chemical sensors that regulate flagellar motility. Cell Motil. and Cytoske. 57:8-17.
Yang, P., C. Yang and W.S. Sale. (2004). Flagellar radial spoke protein 2 is a calmodulin binging protein required for motility in Chlamydomonas reinhardtii. Euc. Cell 3:72-81.

Yang, P., Diener, D. R. Rosenbaum, J. L. and Sale, W. S. 2001.  Isolation of intact flagellar radial spokes reveals novel spoke-interacting proteins including dynein light chain LC8 and calmodulin. J. Cell Biol.153:1315-1325.

Yang, P., Fox, L. Colbran, R. J. and Sale, W. S. 2000. Protein phosphatases PP1 and PP2A are located in distinct positions in the Chlamydomonas flagellar axoneme. J. Cell Sci. 113: 91-102.
Yang, P., and Sale, W. S. (2000). Casein kinase I is anchored on axonemal doublet microtubules and regulates flagellar dynein phosphorylation and activity. J. Biol. Chem. 275: 18905-18912.

Yang, P. and Sale, W. S. 1998. The 140,000 Mr intermediate chain of Chlamydomonas flagellar inner arm dynein is a WD-repeat protein implicated in dynein arm anchoring. Mol. Biol. Cell 9: 3335-3349.