The Arabidopsis BUB1/MAD3 family protein BMF3 requires BUB3.3 to recruit CDC20 to kinetochores in spindle assembly checkpoint signaling

The spindle assembly checkpoint (SAC) ensures faithful chromosome segregation during cell division by monitoring kinetochore-microtubule attachment. Plants produce both sequence-conserved and diverged SAC components, and it has been largely unknown how SAC activation leads to the assembly of these proteins at unattached kinetochores to prevent cells from entering anaphase. In Arabidopsis thaliana, the noncanonical BUB3.3 protein was detected at kinetochores throughout mitosis, unlike MAD1 and the plant-specific BUB1/MAD3 family protein BMF3 that associated with unattached chromosomes only. When BUB3.3 was lost by a genetic mutation, mitotic cells often entered anaphase with misaligned chromosomes and presented lagging chromosomes after they were challenged by low doses of the microtubule depolymerizing agent oryzalin, resulting in the formation of micronuclei. Surprisingly, BUB3.3 was not required for the kinetochore localization of other SAC proteins or vice versa. Instead, BUB3.3 specifically bound to BMF3 through two internal repeat motifs that were not required for BMF3 kinetochore localization. This interaction enabled BMF3 to recruit CDC20, a downstream SAC target, to unattached kinetochores. Taken together, our findings demonstrate that plant SAC utilizes unconventional protein interactions for arresting mitosis, with BUB3.3 directing BMF3's role in CDC20 recruitment, rather than the recruitment of BUB1/MAD3 proteins observed in fungi and animals. This distinct mechanism highlights how plants adapted divergent versions of conserved cell cycle machinery to achieve specialized SAC control.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:121

Enthalten in:

Proceedings of the National Academy of Sciences of the United States of America - 121(2024), 12 vom: 19. März, Seite e2322677121

Sprache:

Englisch

Beteiligte Personen:

Deng, Xingguang [VerfasserIn]
Peng, Felicia Lei [VerfasserIn]
Tang, Xiaoya [VerfasserIn]
Lee, Yuh-Ru Julie [VerfasserIn]
Lin, Hong-Hui [VerfasserIn]
Liu, Bo [VerfasserIn]

Links:

Volltext

Themen:

Arabidopsis
BUB3
CDC20
Cell Cycle Proteins
Journal Article
Kinetochore
Spindle assembly checkpoint

Anmerkungen:

Date Completed 13.03.2024

Date Revised 27.03.2024

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1073/pnas.2322677121

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM369565681