How Microtubules Build the Spindle Branch by Branch. Author Sophie Travis, Brian Mahon, Sabine Petry Publication Year 2022 Type Journal Article Abstract The microtubule (MT) cytoskeleton provides the architecture that governs intracellular organization and the regulated motion of macromolecules through the crowded cytoplasm. The key to establishing a functioning cytoskeletal architecture is regulating when and where new MTs are nucleated. Within the spindle, the vast majority of MTs are generated through a pathway known as branching MT nucleation, which exponentially amplifies MT number in a polar manner. Whereas other MT nucleation pathways generally require a complex organelle such as the centrosome or Golgi apparatus to localize nucleation factors, the branching site is based solely on a simple, preformed MT, making it an ideal system to study MT nucleation. In this review, we address recent developments in characterizing branching factors, the branching reaction, and its regulation, as well as branching MT nucleation in systems beyond the spindle and within human disease. Keywords Humans, Microtubule-Associated Proteins, Microtubules, Spindle Apparatus, Tubulin, Microtubule-Organizing Center Journal Annu Rev Cell Dev Biol Volume 38 Pages 1-23 Date Published 2022 Oct 06 ISSN Number 1530-8995 DOI 10.1146/annurev-cellbio-120420-114559 Alternate Journal Annu Rev Cell Dev Biol PMCID PMC9619725 PMID 35759800 PubMedPubMed CentralGoogle ScholarBibTeXEndNote X3 XML