My laboratory uses the unicellular green alga Chlamydomonas to study the biology of cilia and flagella and to dissect cellular and molecular mechanisms of fertilization. Chlamydomonas gametes use their flagella as sensory organelles to transduce receptor-ligand interactions into intracellular responses that prepare them for cell-cell fusion. We study intraflagellar mechanisms that underly signal transduction, and the cellular mechanisms that dynamically regulate flagellar membrane protein composition and flagellar length. In our studies of gamete fusion, we use a multidisciplinary, comparative approach to identify conserved mechanisms of membrane fusion and early steps in zygote development in Chlamydomonas and the malaria pathogen Plasmodium.
Almost all vertebrate cells possess a primary cilium that is used to transduce extracellular signals. We exploit Chlamydomonas to examine intraflagellar mechanisms and pathways that transduce flagellar adhesion into a cellular response.
In collaborative studies with Dr. Junmin Pan of Tsinghua University, Beijing, China, we are studying the role of an aurora-like protein kinase, intraflagellar transport, and a depolymerizing kinesin in flagellar assembly, disassembly, and length control.
We established that the membrane fusion reaction requires a species-specific protein for membrane adhesion, and a conserved protein, HAP2, for membrane merger in Chlamydomonas.
In collaborative studies with Dr. Robert Sinden of Imperial College, London, and Dr. Oliver Billker, Sanger Genome Center, Cambridge, UK, we showed that the malaria organism Plasmodium also uses HAP2 for the membrane fusion reaction. With Dr. Billker, we are using comparative transcriptomics to identify additional conserved sexual reproduction genes.