TY - JOUR
T1 - A dynamically assembled cell wall synthesis machinery buffers cell growth
AU - Lee, Timothy K.
AU - Tropini, Carolina
AU - Hsin, Jen
AU - Desmarais, Samantha M.
AU - Ursell, Tristan S.
AU - Gong, Enhao
AU - Gitai, Zemer
AU - Monds, Russell D.
AU - Huang, Kerwyn Casey
PY - 2014/3/25
Y1 - 2014/3/25
N2 - Assembly of protein complexes is a key mechanism for achieving spatial and temporal coordination in processes involving many enzymes. Growth of rod-shaped bacteria is a well-studied example requiring such coordination; expansion of the cell wall is thought to involve coordination of the activity of synthetic enzymes with the cytoskeleton via a stable complex. Here, we use single-molecule tracking to demonstrate that the bacterial actin homolog MreB and the essential cell wall enzyme PBP2 move on timescales orders of magnitude apart, with drastically different characteristic motions. Our observations suggest that PBP2 interacts with the rest of the synthesis machinery through a dynamic cycle of transient association. Consistent with this model, growth is robust to large fluctuations in PBP2 abundance. In contrast to stable complex formation, dynamic association of PBP2 is less dependent on the function of other components of the synthesis machinery, and buffers spatially distributed growth against fluctuations in pathway component concentrations and the presence of defective components. Dynamic association could generally represent an efficient strategy for spatiotemporal coordination of protein activities, especially when excess concentrations of system components are inhibitory to the overall process or deleterious to the cell.
AB - Assembly of protein complexes is a key mechanism for achieving spatial and temporal coordination in processes involving many enzymes. Growth of rod-shaped bacteria is a well-studied example requiring such coordination; expansion of the cell wall is thought to involve coordination of the activity of synthetic enzymes with the cytoskeleton via a stable complex. Here, we use single-molecule tracking to demonstrate that the bacterial actin homolog MreB and the essential cell wall enzyme PBP2 move on timescales orders of magnitude apart, with drastically different characteristic motions. Our observations suggest that PBP2 interacts with the rest of the synthesis machinery through a dynamic cycle of transient association. Consistent with this model, growth is robust to large fluctuations in PBP2 abundance. In contrast to stable complex formation, dynamic association of PBP2 is less dependent on the function of other components of the synthesis machinery, and buffers spatially distributed growth against fluctuations in pathway component concentrations and the presence of defective components. Dynamic association could generally represent an efficient strategy for spatiotemporal coordination of protein activities, especially when excess concentrations of system components are inhibitory to the overall process or deleterious to the cell.
KW - Bacterial cell wall
KW - Multienzyme complexes
KW - Pencillin binding proteins
KW - Superresolution microscopy
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UR - http://www.scopus.com/inward/citedby.url?scp=84896967755&partnerID=8YFLogxK
U2 - 10.1073/pnas.1313826111
DO - 10.1073/pnas.1313826111
M3 - Article
C2 - 24550500
AN - SCOPUS:84896967755
SN - 0027-8424
VL - 111
SP - 4554
EP - 4559
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 12
ER -