New Modes of GPCR Signalling

Quantitative Phosphoproteome Analysis Reveals Signaling Events
Involved in Aroma-Stimulated Mouse Olfactory Bulbs
Lei-Ke Zhang1, Fei Liu2, Xiao-Ping Rao2, Fu-Qiang Xu2, Lin Guo1
1College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China
2 State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics,
Wuhan Centre for Magnetic Resonance, Wuhan Institute of Physics and Mathematics,
Chinese Academy of Sciences,Wuhan 430071, P.R.China
Stimulation of odorant molecules is transduced by olfactory receptor neurons (ORNs)
located in the olfactory epithelium of the nasal cavities. Each ORN projects a single
axon to the main olfactory bulb (MOB), where it terminates on the second-order
neurons of the MOB in glomeruli, the initial site for the coding and processing of odor
information. In the glomeruli, ORN axons terminate on the dendrites of mitral/tufted
cells, which in turn project into higher cortical structures. The activity in the MOB is
determined by the input from the SONs, the centrifugal inputs that include regulatory
and feedback fibers from many brain regions, and the nerurocircuits within the MOB.
Finding the proteins that are involved in responding to olfactory stimulation can help to
reveal the mechanism of sensory information processing. Here, signaling events in
odor-stimulated MOBs were explored using quantitative phosphoproteomic analysis.
Our preliminary results showed that a 10 mg protein mixture from the MOB lysate
resulted in the identification and quantification of >1000 unique phosphorylation sites
and ~700 unique phosphoproteins. Further analysis revealed that many up- or
down-regulated phosphorylation events were known having functions in signal
transductuon after odor stimulating. For example, Thr-34 of DCLK1 isoform 1
(accession number: IPI00468380) was up-regulated 8 fold, and Ser-181 of Pgrmc1
(accession number: IPI00319973) was down-regulated 2.13 fold.