Linked Life Data

3522607

Source:http://linkedlifedata.com/resource/pubmed/id/3522607

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1986-8-8
pubmed:abstractText
Light-dependent reduction of the plastoquinone pool regulates the activity of the thylakoid-bound protein kinase which phosphorylates the light harvesting chlorophyll a,b-protein complex (LHC II) and regulates energy distribution between photosystems II (PS II) and I (Staehelin, L. A., and C. J. Arntzen, 1983, J. Cell Biol., 97:1327-1337). Since reduction of plastoquinone by PS II is abolished in photoinhibited thylakoids due to loss of the secondary electron acceptor QB protein (Kyle, D. J., I. Ohad, and C. J. Arntzen, 1984, Proc. Natl. Acad. Sci. USA, 81:4070-4074), it was of interest to examine the activity of the LHC II protein kinase system during photoinhibition and recovery of PS II activity. The kinase activity was assessed both in vivo and in vitro in Chlamydomonas cells exposed to high light intensity (photoinhibition) and recovery at low light intensity. The kinase activity was progressively reduced during photoinhibition and became undetectable after 90 min. The inactive LHC II-kinase system could not be reactivated in vitro either by light or by reduction of the plastoquinone pool following addition of reduced duroquinone (TMQH2). The LHC II polypeptides were dephosphorylated in vivo when cells, prelabeled with [32P]orthophosphate before exposure to high light intensity, were transferred to photoinhibiting light in the presence of [32P]orthophosphate. In vivo recovery of the LHC II-kinase activity, elicited by the addition of TMQH2 to the assay system, did not require restoration of QB-dependent electron flow or de novo protein synthesis, either in the cytoplasm or in the chloroplast. Mild sonication of thylakoids isolated from photoinhibited cells restored the ability of the LHC II protein kinase system to be activated in vitro by addition to TMQH2. Restoration of the light-activated LHC-II kinase required recovery of QB-dependent electron flow. At the structural level, photoinhibition did not affect the ratio of grana/stroma thylakoids. A reduction of approximately 20% of the 11-17-nm intramembrane particles and an equivalent increase in the number of 6-10.5-nm particles was observed on the E-fracture faces of stacked thylakoid membranes. Similar but smaller changes were observed also on the E-fracture faces of unstacked thylakoid membranes (more 10-14-nm and less 6-9-nm particles) and P-fracture faces of stacked thylakoid membranes (more 6-8- and less 9.5-13-nm particles). All these structural changes were reversed to normal values during recovery of PS II activity.(ABSTRACT TRUNCATED AT 400 WORDS)
pubmed:grant
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/3522607-16593210, http://linkedlifedata.com/resource/pubmed/commentcorrection/3522607-16593434, http://linkedlifedata.com/resource/pubmed/commentcorrection/3522607-16593483, http://linkedlifedata.com/resource/pubmed/commentcorrection/3522607-16654194, http://linkedlifedata.com/resource/pubmed/commentcorrection/3522607-4044582, http://linkedlifedata.com/resource/pubmed/commentcorrection/3522607-4196359, http://linkedlifedata.com/resource/pubmed/commentcorrection/3522607-467680, http://linkedlifedata.com/resource/pubmed/commentcorrection/3522607-5432063, http://linkedlifedata.com/resource/pubmed/commentcorrection/3522607-6064364, http://linkedlifedata.com/resource/pubmed/commentcorrection/3522607-6355117, http://linkedlifedata.com/resource/pubmed/commentcorrection/3522607-6378924, http://linkedlifedata.com/resource/pubmed/commentcorrection/3522607-6811597, http://linkedlifedata.com/resource/pubmed/commentcorrection/3522607-6847199, http://linkedlifedata.com/resource/pubmed/commentcorrection/3522607-6933557, http://linkedlifedata.com/resource/pubmed/commentcorrection/3522607-7118935, http://linkedlifedata.com/resource/pubmed/commentcorrection/3522607-870501
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0021-9525
pubmed:author
pubmed:issnType
Print
pubmed:volume
103
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
71-80
pubmed:dateRevised
2010-9-10
pubmed:meshHeading
pubmed:year
1986
pubmed:articleTitle
Transient inactivation of the thylakoid photosystem II light-harvesting protein kinase system and concomitant changes in intramembrane particle size during photoinhibition of Chlamydomonas reinhardtii.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't