Structural and Molecular Mechanisms of Centrosome Assembly and Strength

The outermost layer of centrosomes, called pericentriolar material (PCM), organizes microtubules for mitotic spindle assembly. The molecular interactions that enable PCM to assemble and resist external forces are poorly understood. To answer such question, we use cross-linking mass spectrometry (XL-MS) to analyze PLK-1-potentiated multimerization of SPD-5, the main PCM scaffold protein in C. elegans. In the unassembled state, SPD-5 exhibits numerous intramolecular interactions that are eliminated after phosphorylation by PLK-1. Thus, phosphorylation induces a structural opening of SPD-5 that primes it for assembly. Multimerization of SPD-5 is driven by interactions between multiple dispersed coiled-coil domains. Structural analyses of a phosphorylated region (PReM) in SPD-5 revealed a helical hairpin that dimerizes to form a tetrameric coiled-coil. Mutations within this structure and other interacting regions cause PCM assembly defects that are partly rescued by eliminating microtubule-mediated forces, revealing that PCM assembly and strength are interdependent. We propose that PCM size and strength emerge from specific, multivalent coiled-coil interactions between SPD-5 proteins.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Cell and Molecular Biology

Grantor

UT Southwestern Medical Center

Year dc:date.issued

2024

Author dc:creator

• Rios, Manolo Uriel

Advisor dc:contributor.advisor

• Doubrovinski, Konstantin

Committee members dc:contributor.committeemember

• Rosen, Michael K.
• Woodruff, Jeffrey B.
• Seemann, Joachim

• Cell Cycle Proteins
• Centrosome
• Polo-Like Kinase 1
• Caenorhabditis elegans

Language dc:language.iso

en

Identifier

1438579295

OAI record oai:identifier

https://utswmed-ir.tdl.org/server/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Autswmed-ir.tdl.org%3A2152.5%2F10315