GSBS Student Publications

Title

Pericentrin and gamma-tubulin form a protein complex and are organized into a novel lattice at the centrosome

GSBS Program

Biochemistry & Molecular Pharmacology

UMMS Affiliation

Graduate School of Biomedical Sciences; Program in Molecular Medicine and Department of Cell Biology

Date

5-16-1998

Document Type

Article

Medical Subject Headings

Animals; Antigens; CHO Cells; COS Cells; Cell Cycle; Cell Fractionation; Cells, Cultured; Centrifugation, Density Gradient; Centrosome; Chromatography, Gel; Cricetinae; Fluorescent Antibody Technique; Microtubule-Associated Proteins; Microtubules; Tubulin; Xenopus

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

Pericentrin and gamma-tubulin are integral centrosome proteins that play a role in microtubule nucleation and organization. In this study, we examined the relationship between these proteins in the cytoplasm and at the centrosome. In extracts prepared from Xenopus eggs, the proteins were part of a large complex as demonstrated by sucrose gradient sedimentation, gel filtration and coimmunoprecipitation analysis. The pericentrin-gamma-tubulin complex was distinct from the previously described gamma-tubulin ring complex (gamma-TuRC) as purified gamma-TuRC fractions did not contain detectable pericentrin. When assembled at the centrosome, the two proteins remained in close proximity as shown by fluorescence resonance energy transfer. The three- dimensional organization of the centrosome-associated fraction of these proteins was determined using an improved immunofluorescence method. This analysis revealed a novel reticular lattice that was conserved from mammals to amphibians, and was organized independent of centrioles. The lattice changed dramatically during the cell cycle, enlarging from G1 until mitosis, then rapidly disassembling as cells exited mitosis. In cells colabeled to detect centrosomes and nucleated microtubules, lattice elements appeared to contact the minus ends of nucleated microtubules. Our results indicate that pericentrin and gamma-tubulin assemble into a unique centrosome lattice that represents the higher-order organization of microtubule nucleating sites at the centrosome.

Rights and Permissions

Citation: J Cell Biol. 1998 Apr 6;141(1):163-74.

Related Resources

Link to article in PubMed

Journal Title

The Journal of cell biology

PubMed ID

9531556