[Seminars] PSB event reminder

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Calendar Name: seminars
Scheduled for: Monday, July 1 2013, 14:00 - 15:30
Event text:    Prof Klaas Van Wijk
	       
	       Department of Plant Biology
	       Cornell University
	       
	       Ithaca
	       NY
	       USA
Details:       “Plastoglobules and their ABC1 Kinases in Arabidopsis
	       thaliana”
	       
	       ABSTRACT
	       Plastoglobules (PG) are plastid lipid-protein particles
	       with a small specialized proteome and metabolome. In my
	       talk I will provide evidence that PG function as
	       thylakoid microdomains facilitating concentration of
	       metabolites and proteins to accommodate metabolic
	       channeling and higher flux rates, as well as signal
	       transduction. 
	       We constructed a comprehensive functional model of the
	       PG based on co-expression analysis using identified PG
	       proteins as baits. The resulting co-expression network
	       implicated four specific functions for the PG: i)
	       senescence, ii) plastid biogenesis, iii) prenyl-lipid
	       metabolism, and iv) redox/photosynthetic regulation.
	       Among the 30 PG proteins are six proteins of the ancient
	       ABC1 atypical kinase (ABC1K) family and their locations
	       in the co-expression network suggested important
	       regulatory roles. Algae and higher plants have typically
	       more than 16 ABC1Ks members, where they localize to
	       plastids and mitochondria. We hypothesized that targets
	       of ABC1Ks include enzymes of prenyl-lipid metabolism as
	       well as components of the organellar gene expression
	       machineries. Loss of function mutants for PG-localized
	       ABC1K1 and ABC1K3 in Arabidopsis thaliana show
	       conditional senescence-like phenotypes, involving
	       degradation of the PSII core and upregulation of
	       chlorophyll degradation. The senescence-like phenotype
	       was independent of the EXECUTER pathway and correlated
	       with increased levels of the 1O2-derived carotenoid
	       β-cyclocitral, a retrograde plastid signal.
	       Metabolite and proteome analyses show that ABC1K1/3
	       contribute to PG function in prenyl-lipid metabolism,
	       stress response and thylakoid remodeling, and contribute
	       to cross-talk between the thylakoid and the Calvin
	       cycle.
	       
		
	       Ytterberg, A.J., Peltier, J.B., and van Wijk, K.J.
	       (2006). Protein profiling of plastoglobules in
	       chloroplasts and chromoplasts; a surprising site for
	       differential accumulation of metabolic enzymes. Plant
	       Physiol 140, 984-997.
	       Brehelin, C., Kessler, F., and van Wijk, K.J. (2007).
	       Plastoglobules: versatile lipoprotein particles in
	       plastids. Trends Plant Sci 12, 260-266.
	       Lundquist, P., Poliakov, A., Bhuiyan, N.H., Zybailov,
	       B., Sun, Q., and van Wijk, K.J. (2012a). The functional
	       network of the Arabidopsis thaliana plastoglobule
	       proteome based on quantitative proteomics and
	       genome-wide co-expression analysis. Plant Physiol 58,
	       1172-1192.
	       Lundquist, P.K., Davis, J.I., and van Wijk, K.J.
	       (2012b). ABC1K atypical kinases in plants: filling the
	       organellar kinase void. Trends Plant Sci 17, 546-555.
	       Lundquist, P., Poliakov, A., Giacomelli, L., Friso, G.,
	       Appel, M., McQuinn, R.P., Krasnoff, S.B., Rowland, O.,
	       Ponnala, L., Sun, Q., and van Wijk, K.J. (2013). Loss of
	       plastoglobule-localized kinases ABC1K1 and ABC1K3 leads
	       to a conditional degreening phenotype, a modified
	       prenyl-lipid composition and recruitment of JA
	       biosynthesis. Plant Cell - prepublication online.

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