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Diffusion of a membrane protein, Tat subunit Hcf106, is highly restricted within the chloroplast thylakoid network
Author(s) -
Vladimirou Elina,
Li Michael,
Aldridge Cassie P.,
Frigerio Lorenzo,
Kirkilionis Markus,
Robinson Colin
Publication year - 2009
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2009.10.057
Subject(s) - thylakoid , photobleaching , fluorescence recovery after photobleaching , protein subunit , photosystem ii , biophysics , chloroplast , membrane protein , green fluorescent protein , membrane , transport protein , chemistry , lipid bilayer fusion , biology , biochemistry , fluorescence , photosynthesis , physics , optics , gene
The thylakoid membrane forms stacked thylakoids interconnected by ‘stromal’ lamellae. Little is known about the mobility of proteins within this system. We studied a stromal lamellae protein, Hcf106, by targeting an Hcf106‐GFP fusion protein to the thylakoids and photobleaching. We find that even small regions fail to recover Hcf106‐GFP fluorescence over periods of up to 3 min after photobleaching. The protein is thus either immobile within the thylakoid membrane, or its diffusion is tightly restricted within distinct regions. Autofluorescence from the photosystem II light‐harvesting complex in the granal stacks likewise fails to recover. Integral membrane proteins within both the stromal and granal membranes are therefore highly constrained, possibly forming ‘microdomains’ that are sharply separated.