Gene Ontology annotation through association of InterPro records with GO terms
A Rubisco-binding protein is required for normal pyrenoid number and starch sheath morphology in Chlamydomonas reinhardtii.
-
SAGA1 carries a CBM20 starch-binding motif with all conserved binding residues; starch binding was predicted but not tested
"All 5 highly conserved residues necessary for starch binding are present in SAGA1, suggesting that SAGA1 can bind starch"
-
SAGA1 binds Rubisco large and small subunits but not EPYC1 in yeast two-hybrid assays
"In this assay, SAGA1 interacted with the large and small subunits of Rubisco, but not with EPYC1 (Fig. 5A)."
-
SAGA1 is required for a functional CCM
"We conclude from these observations that SAGA1 is required for a functional CCM and for maximal CO2 uptake in cells acclimated to both low and high CO2."
-
SAGA1-Venus localizes to the pyrenoid as puncta and streaks
"We conclude that SAGA1-Venus localizes to the pyrenoid."
-
Most saga1 mutant pyrenoids lack the thylakoid tubule network
"However, nearly all pyrenoids of the saga1 mutant lacked such hallmark thylakoid tubules"
Assembly of the algal CO(2)-fixing organelle, the pyrenoid, is guided by a Rubisco-binding motif.
-
SAGA1 carries the shared pyrenoid Rubisco-binding motif and is proposed to tie the matrix to the starch sheath
"At the periphery of the matrix, the motif on starch-binding proteins SAGA1 and SAGA2 mediates interactions between the matrix and surrounding starch sheath."
-
SAGA1 localizes at the matrix-starch sheath interface
"As described previously (14), SAGA1 localized to puncta at the periphery of the matrix, likely at the interface between the Rubisco matrix and the starch sheath."
SAGA1 and MITH1 produce matrix-traversing membranes in the CO(2)-fixing pyrenoid.
-
SAGA1 is necessary to initiate matrix-traversing membranes
"SAGA1 is necessary for the initiation of matrix-traversing membranes as recognized by CYN7 (Fig. 3m–o) and CAH3 (Extended Data Fig. 8)."
-
SAGA1 and MITH1 together are sufficient to make thylakoid membranes traverse a Rubisco condensate in Arabidopsis
"These results demonstrate that SAGA1 and MITH1 together are sufficient to generate matrix-traversing thylakoid membranes in a heterologous system."
-
SAGA1 localizes throughout the matrix-traversing membranes, enriched at their periphery
"Our results indicate that in Chlamydomonas, SAGA1 localizes throughout the matrix-traversing membranes and is enriched in puncta at their periphery."
-
SAGA1 localization does not require starch
"indicating that SAGA1 does not require starch for its normal localization"
-
SAGA1 associates with membranes in cell fractionation
"suggesting that while SAGA1 interacts with membranes, a portion of the protein dissociates from membranes during the experiment or exists in a distinct soluble state"
-
SAGA1 and MITH1 physically interact in vivo
"SAGA1 was MITH1’s most-abundant specific interactor, and MITH1 was one of SAGA1’s most-specific interactors, indicating that the two proteins physically interact"
-
Proposed mechanism in which SAGA1 and MITH1 provide Rubisco-membrane bonds
"We propose that SAGA1 and MITH1 together provide such Rubisco-membrane bonds, making it energetically favourable for membranes to traverse the matrix (Fig. 3u)."
Biogenesis, engineering and function of membranes in the CO (2) -fixing pyrenoid.
SAGA1 and SAGA2 localize the starch sheath to the pyrenoid in Chlamydomonas reinhardtii.
-
Purified SAGA1 CBM20 (tandem construct) binds starch granules in vitro; mVenus control does not
"We observed that both the 10×His-mVenus-2×SAGA1-CBM20 and the 10×His-mVenus-SAGA2-2×CBM20 proteins, but not a 10×His-mVenus control protein, bound to starch"
-
SAGA1 CBM20 also binds the starch precursor maltoheptaose and the mimic beta-cyclodextrin
"We conclude that both the SAGA1 CBM20 domain and the SAGA2 CBM20 domain can bind to not only starch but also to starch precursor molecules"
-
SAGA1 is enriched at starch-tubule-matrix junctions
"Our results indicate that whereas SAGA1 is enriched at the starch–tubule–matrix junctions of the pyrenoid, SAGA2 is depleted from these regions"
-
SAGA1 and SAGA2 redundantly localize the starch sheath to the pyrenoid
"suggesting that SAGA1 and SAGA2 function redundantly to localize starch sheaths to the pyrenoid"
SAGA1 and SAGA2 promote starch formation around proto-pyrenoids in Arabidopsis chloroplasts.
-
Heterologous SAGA1 rings the Rubisco condensate and recruits starch to it in Arabidopsis
"We found that SAGA1 did indeed recruit starch to the proto-pyrenoid condensate in Arabidopsis, including extended plate-like starch granules at the edge of the condensate."
Super-resolution expansion microscopy reveals nanoscale protein domains and CO(2)-dependent remodeling of Chlamydomonas pyrenoid-traversing membranes.
A pyrenoid-localized protein SAGA1 is necessary for Ca(2+)-binding protein CAS-dependent expression of nuclear genes encoding inorganic carbon transporters in Chlamydomonas reinhardtii.
-
saga1 mutants fail to express CAS-dependent Ci-transporter genes and mislocalize CAS
"Among them, 10 CAS-dependent genes, including HLA3 and LCIA, were not expressed in the saga1 mutants."
A Spatial Interactome Reveals the Protein Organization of the Algal CO(2)-Concentrating Mechanism.