The N-terminus of Sfi1 and yeast centrin Cdc31 provide the assembly site for a new spindle pole body.
The spindle pole body (SPB) provides microtubule-organizing functions in yeast and duplicates exactly once per cell cycle. The first step in SPB duplication is the half-bridge to bridge conversion via the antiparallel dimerization of the centrin (Cdc31)-binding protein Sfi1 in anaphase. The bridge, which is anchored to the old SPB ... on the proximal end, exposes free Sfi1 N-termini (N-Sfi1) at its distal end. These free N-Sfi1 promote in G1 the assembly of the daughter SPB (dSPB) in a yet unclear manner. This study shows that N-Sfi1 including the first three Cdc31 binding sites interacts with the SPB components Spc29 and Spc42, triggering the assembly of the dSPB. Cdc31 binding to N-Sfi1 promotes Spc29 recruitment and is essential for satellite formation. Furthermore, phosphorylation of N-Sfi1 has an inhibitory effect and delays dSPB biogenesis until G1. Taking these data together, we provide an understanding of the initial steps in SPB assembly and describe a new function of Cdc31 in the recruitment of dSPB components.
Mesh Terms:
Amino Acid Sequence, Anaphase, Binding Sites, Calcium-Binding Proteins, Cell Cycle Proteins, Cytoskeletal Proteins, Mutant Proteins, Mutation, Phosphoproteins, Phosphorylation, Protein Binding, Protein Kinases, Repressor Proteins, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Spindle Pole Bodies, Structure-Activity Relationship
Amino Acid Sequence, Anaphase, Binding Sites, Calcium-Binding Proteins, Cell Cycle Proteins, Cytoskeletal Proteins, Mutant Proteins, Mutation, Phosphoproteins, Phosphorylation, Protein Binding, Protein Kinases, Repressor Proteins, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Spindle Pole Bodies, Structure-Activity Relationship
J Cell Biol
Date: Dec. 01, 2020
PubMed ID: 33523111
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