The role of Bni5 in the regulation of septin higher-order structure formation.
Septins are a family of conserved cytoskeletal proteins playing an essential role in cytokinesis and in many other cellular processes in fungi and animals. In budding yeast Saccharomyces cerevisiae, septins form filaments and higher-order structures at the mother-bud neck depending on the particular stage of the cell cycle. Septin structures at the division plane serve as a scaffold to recruit the proteins required for particular cellular processes. The formation and localization of septin structures at particular stages of the cell cycle also determine functionality of these proteins. Many different proteins participate in regulating septin assembly. Despite recent developments, we are only beginning to understand how specific protein-protein interactions lead to changes in the polymerization of septin filaments or assembly of higher-order structures. Here, using fluorescence and electron microscopy, we found that Bni5 crosslinks septin filaments into networks by bridging pairs or multiple filaments, forming structures that resemble railways. Furthermore, Bni5 appears to be a substrate of the Elm1 protein kinase in vitro. Moreover, Elm1 induces in the presence of Bni5 disassembly of long septin filaments, suggesting that these proteins may participate in the hourglass to double ring transition. This work gives new insight into the regulatory role of Bni5 in the structural changes of septins.
Csilla
C
Patasi
Jana
J
Godočíková
Soňa
S
Michlíková
Yan
Y
Nie
Radka
R
Káčeriková
Katarína
K
Kválová
Stefan
S
Raunser
Marian
M
Farkašovský
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology; D011494:Protein Kinases / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000201:enzymology / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D058112:Septins / Q000737:chemistry / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; C466084:BNI5 protein, S cerevisiae; C109252:GIC1 protein, S cerevisiae; C109253:GIC2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D011494:Protein Kinases; C411302:ELM1 protein, S cerevisiae; D058112:Septins