"The proteins we named Rubisco-binding membrane proteins RBMP1 (Cre06.g261750) and RBMP2 (Cre09.g416850) have predicted transmembrane domains and were previously found to bind to Rubisco"

"SAGA2, RBMP1, RBMP2, and CSP41A by affinity purification–mass spectrometry (18)"

"Arrays of 18–amino acid peptides tiling across the sequences of SAGA2 (B) and RBMP2 (C) were synthesized and probed with Rubisco."

"Fluorescently tagged RBMP1 and RBMP2 localized to the tubules"

"Our microscopy data suggest that RBMP2 is confined to the central reticulated region of the tubules"

"the presence of the same motif on the pyrenoid tubule-localized transmembrane proteins, RBMP1 and RBMP2, recruits Rubisco to the tubules and favors assembly of the matrix around them"

"The predicted transmembrane protein RBMP2 localizes to the reticulated region27"

"We show that RBMP2 loss eliminates this central reticulated membrane network, mislocalizes CAH3 and impairs growth under very low CO2."

"We conclude that RBMP2 is required for normal CAH3 localization and for maintaining pyrenoid function under strongly CO2-limiting conditions."

"Together, these results indicate that RBMP2 is required for reticulated-region formation."

"Thus, RBMP2 is not only required for reticulated-region formation; overexpressing the RBMP2 protein is sufficient to promote the expansion of the reticulated region in wild-type cells."

"In the rbmp2 mutant, cylindrical tubules still extended from the pyrenoid periphery toward the center, but we never observed them forming a reticulated network"

"RBMP2 contains an N-terminal region with predicted membrane-contact probability (MCP)33, a central non-catalytic rhodanese domain (RHO), predicted transmembrane helices (TM) on both sides of the RHO domain and six C-terminal Rubisco-binding motifs (RBMs)27"

"The catalytic cysteine residue is marked in green, and the non-catalytic aspartic acid residue in RBMP2 is marked in grey."

"These results suggest that the RHO domain performs an essential and upstream function in reticulated-region biogenesis, likely promoting extension of the tubules."

"MCP and TM domains are not required for cylindrical tubule elongation. Instead, they are required to convert elongated cylindrical tubules into reticulated-region tubules."

"These results suggest that the RBMs are dispensable for detectable reticulated-region formation, although they may still contribute to RBMP2 function in ways not resolved by these assays."

"Tubule and minitubule fusion are likely mediated by factors other than RBMP2"

"However, the presence of a normal reticulated region in the lci16 mutant38 suggests that LCI16 is not essential for reticulated-region biogenesis."

"Meyer et al. (2020) proposed that BST4, together with other tether proteins, may recruit Rubisco to the tubule network."

"Collectively, these data indicate that BST4 may require a preexisting pyrenoid tubule network to be localized in the pyrenoid rather than driving the inclusion of thylakoid membranes into the Rubisco matrix or is redundant as a tether protein."

"Why the pyrenoid-traversing membranes exhibit these two distinct morphological domains remains a major open question in the field."

"notably suggesting a role for the central reticulated region in localizing the essential CO2-delivering carbonic anhydrase CAH3"

"RBMP2 is considerably larger (165 kDa) and contains a long stromal C-terminal region with six RBMs."

"including those found on the key pyrenoid proteins SAGA1, SAGA2, RBMP1, RBMP2 and CSP41A, bind to Rubisco"