Protein translocation and thylakoid biogenesis in cyanobacteria.
Cyanobacteria exhibit a complex form of membrane differentiation that sets them apart from most bacteria. Many processes take place in the plasma membrane, but photosynthetic light capture, electron transport and ATP synthesis take place in an abundant internal thylakoid membrane. This review considers how this system of subcellular compartmentalisation is maintained, and how proteins are directed towards the various subcompartments--specifically the plasma membrane, periplasm, thylakoid membrane and thylakoid lumen. The involvement of Sec-, Tat- and signal recognition particle- (SRP)-dependent protein targeting pathways is discussed, together with the possible involvement of a so-called 'spontaneous' pathway for the insertion of membrane proteins, previously characterised for chloroplast thylakoid membrane proteins. An intriguing aspect of cyanobacterial cell biology is that most contain only a single set of genes encoding Sec, Tat and SRP components, yet the proteomes of the plasma and thylakoid membranes are very different. The implications for protein sorting mechanisms are considered. This article is part of a Special Issue entitled Organization and dynamics of bioenergetic systems in bacteria, edited by Prof Conrad Mullineaux.
Centre for Molecular Processing, School of Biosciences, University of Kent, Ingram Building, Canterbury, CT2 7NJ, United Kingdom.
Kelly M
KM
Frain
Centre for Molecular Processing, School of Biosciences, University of Kent, Ingram Building, Canterbury, CT2 7NJ, United Kingdom.
Doris
D
Gangl
Centre for Molecular Processing, School of Biosciences, University of Kent, Ingram Building, Canterbury, CT2 7NJ, United Kingdom.
Alexander
A
Jones
Centre for Molecular Processing, School of Biosciences, University of Kent, Ingram Building, Canterbury, CT2 7NJ, United Kingdom.
Julie A Z
JA
Zedler
Centre for Molecular Processing, School of Biosciences, University of Kent, Ingram Building, Canterbury, CT2 7NJ, United Kingdom. Electronic address: C.Robinson-504@kent.ac.uk.
Colin
C
Robinson
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D000458:Cyanobacteria / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D020524:Thylakoids / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins
Cyanobacteria; Membrane biogenesis; Protein translocation; SRP; Sec; Tat