Sites of phospholipid biosynthesis during induction of intracytoplasmic membrane formation in Rhodopseudomonas sphaeroides

The accumulation of N-acylphosphatidylserine (NAPS) in response to the inclusion of Tris in the growth medium of Rhodopseudomonas sphaeroides strain M29-5 has been examined. In the accompanying paper (Donohue et al., J. Bacteriol. 152:000--000, 1982), we show that in response to Tris, NAPS accumulated to as much as 40% of the total cellular phospholipid content. NAPS accumulation began immediately upon addition of Tris and was reflected as an abrupt 12-fold increase in the apparent rate of NAPS accumulation. We suggest that Tris altered the flow of metabolites through a preexisting and previously unknown metabolic pathway. NAPS accumulation ceased immediately upon the removal of Tris; however, accumulated NAPS remained largely metabolically stable. Importantly, under conditions in which NAPS was not accumulated, the intracytoplasmic membrane was shown to be virtually devoid of newly synthesized NAPS. The significance of this observation is discussed in terms of its physiological implications on phospholipid transfer and membrane biogenesis in R. sphaeroides.

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Monomeric RC–LH1 core complexes retard LH2 assembly and intracytoplasmic membrane formation in PufX-minus mutants of Rhodobacter sphaeroides

Biochimica et Biophysica Acta (BBA) - Bioenergetics ◽

10.1016/j.bbabio.2011.05.019 ◽

2011 ◽

Vol 1807 (9) ◽

pp. 1044-1055 ◽

Cited By ~ 19

Author(s):

Peter G. Adams ◽

David J. Mothersole ◽

Irene W. Ng ◽

John D. Olsen ◽

C. Neil Hunter

Keyword(s):

Rhodobacter Sphaeroides ◽

Intracytoplasmic Membrane ◽

Membrane Formation

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Forms, Crosstalks, and the Role of Phospholipid Biosynthesis in Autophagy

International Journal of Cell Biology ◽

10.1155/2012/931956 ◽

2012 ◽

Vol 2012 ◽

pp. 1-10 ◽

Cited By ~ 17

Author(s):

Leanne Pereira ◽

John Paul Girardi ◽

Marica Bakovic

Keyword(s):

Phospholipid Synthesis ◽

Phospholipid Biosynthesis ◽

Lysosomal Degradation ◽

Specific Mechanism ◽

Membrane Formation ◽

Cytoplasmic Material ◽

Specific Proteins ◽

Chaperone Mediated Autophagy ◽

Periods Of Stress

Autophagy is a highly conserved cellular process occurring during periods of stress to ensure a cell's survival by recycling cytosolic constituents and making products that can be used in energy generation and other essential processes. Three major forms of autophagy exist according to the specific mechanism through which cytoplasmic material is transported to a lysosome. Chaperone-mediated autophagy is a highly selective form of autophagy that delivers specific proteins for lysosomal degradation. Microautophagy is a less selective form of autophagy that occurs through lysosomal membrane invaginations, forming tubes and directly engulfing cytoplasm. Finally, macroautophagy involves formation of new membrane bilayers (autophagosomes) that engulf cytosolic material and deliver it to lysosomes. This review provides new insights on the crosstalks between different forms of autophagy and the significance of bilayer-forming phospholipid synthesis in autophagosomal membrane formation.

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