The long term goals of my research are to understand the molecular mechanisms of specific cell-cell recognition and establish how these events at the cell surface lead to secondary responses by cells. I have chosen the mating reaction (fertilization) of the biflagellated alga, Chlamydomonas reinhardtii, as a model system for these studies. Fertilization is initiated in this organism when gametes of opposite mating types (mt+ and mt-) adhere to each other via adhesion molecules, agglutinins, on their flagellar surfaces. Agglutinin interactions initiate a complex series of events, termed gamete activation, that prepare the interacting gametes for cell fusion. Early during gamete activation, flagellar protein kinases couple agglutinin interactions to activation of adenylyl cyclase. Later, agglutinins synthesis is upregulated and agglutinins translocate to the flagella. We have identified three biochemical events that are markers of gamete activation, including inhibition of a flagellar protein kinase; phosphorylation of a newly discovered mt+ gamete specific homeodomain protein, GSP1; and gamete activation-induced translocation of a recently discovered aurora/IpI1-like protein kinase from the cell body to the flagella. The research described in this application aims to accomplish the following: 1) Study the biochemical and molecular mechanisms that couple increases in cAMP to phosphorylation of GSP1 homeodomain protein; 2) Examine the function of GSP1 in mt+ gametes; 3) Investigate cellular and molecular properties of the CALK aurora/IpI1-like protein kinase; and 4) Study regulation of the phosphorylation state of the protein kinase, SksC. These studies should provide new information about biochemical and molecular mechanisms of gamete activation and cellular responses induced by cell-cell interactions, which are important in the proper functioning of the immune system, in metastasis, and in fertilization and early development.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM025661-24
Application #
6518969
Study Section
Special Emphasis Panel (ZRG1-CDF-1 (01))
Program Officer
Anderson, Richard A
Project Start
1978-07-01
Project End
2004-05-31
Budget Start
2002-06-01
Budget End
2003-05-31
Support Year
24
Fiscal Year
2002
Total Cost
$347,640
Indirect Cost
Name
University of Texas Sw Medical Center Dallas
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
City
Dallas
State
TX
Country
United States
Zip Code
75390
Cao, Muqing; Ning, Jue; Hernandez-Lara, Carmen I et al. (2015) Uni-directional ciliary membrane protein trafficking by a cytoplasmic retrograde IFT motor and ciliary ectosome shedding. Elife 4:
Haubrich, Brad A; Collins, Emily K; Howard, Alicia L et al. (2015) Characterization, mutagenesis and mechanistic analysis of an ancient algal sterol C24-methyltransferase: Implications for understanding sterol evolution in the green lineage. Phytochemistry 113:64-72
Pan, Junmin; Snell, William J (2014) Organelle size: a cilium length signal regulates IFT cargo loading. Curr Biol 24:R75-8
Cao, Muqing; Meng, Dan; Wang, Liang et al. (2013) Activation loop phosphorylation of a protein kinase is a molecular marker of organelle size that dynamically reports flagellar length. Proc Natl Acad Sci U S A 110:12337-42
Belzile, Olivier; Hernandez-Lara, Carmen I; Wang, Qian et al. (2013) Regulated membrane protein entry into flagella is facilitated by cytoplasmic microtubules and does not require IFT. Curr Biol 23:1460-5
Ning, Jue; Otto, Thomas D; Pfander, Claudia et al. (2013) Comparative genomics in Chlamydomonas and Plasmodium identifies an ancient nuclear envelope protein family essential for sexual reproduction in protists, fungi, plants, and vertebrates. Genes Dev 27:1198-215
Miller, Matthew B; Haubrich, Brad A; Wang, Qian et al. (2012) Evolutionarily conserved Delta(25(27))-olefin ergosterol biosynthesis pathway in the alga Chlamydomonas reinhardtii. J Lipid Res 53:1636-45
Luo, Minna; Cao, Muqing; Kan, Yinan et al. (2011) The phosphorylation state of an aurora-like kinase marks the length of growing flagella in Chlamydomonas. Curr Biol 21:586-91
Rohatgi, Rajat; Snell, William J (2010) The ciliary membrane. Curr Opin Cell Biol 22:541-6
Piao, Tian; Luo, Minna; Wang, Liang et al. (2009) A microtubule depolymerizing kinesin functions during both flagellar disassembly and flagellar assembly in Chlamydomonas. Proc Natl Acad Sci U S A 106:4713-8

Showing the most recent 10 out of 41 publications