A Novel p21-Activated Kinase Binds the Actin and Microtubule Networks and Induces Microtubule Stabilization

• Published in: The Journal of cell biology Vol. 155; no. 6; pp. 1029 - 1042
• Main Authors: Cau, Julien, Faure, Sandrine, Comps, Michel, Delsert, Claude, Morin, Nathalie
• Format: Journal Article
• Language: English
• Published: United States Rockefeller University Press 10-12-2001; The Rockefeller University Press
• Subjects: Actin Cytoskeleton - metabolism; Actins; Actins - metabolism; Amino acids; Animals; Antibodies; Catalytic Domain - physiology; cdc42 GTP-Binding Protein - metabolism; Cell cycle; Cell Line; Cells; Cellular immunity; Cloning, Molecular; Eggs; Epithelial Cells - cytology; Gene Expression Regulation, Enzymologic; Glutamic Acid - metabolism; Green Fluorescent Proteins; Indicator Dilution Techniques; Indicators and Reagents - metabolism; Luminescent Proteins - genetics; Microtubules; Microtubules - metabolism; Molecular Sequence Data; p21-Activated Kinases; Physiological regulation; Polymers - metabolism; Protein Structure, Tertiary; Protein-Serine-Threonine Kinases - chemistry; Protein-Serine-Threonine Kinases - genetics; Protein-Serine-Threonine Kinases - metabolism; rac1 GTP-Binding Protein - metabolism; Sequence Homology, Amino Acid; Stress fibers; Transfection; Tyrosine - metabolism; Xenopus laevis; Xenopus Proteins
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.200104123

Coordination of the different cytoskeleton networks in the cell is of central importance for morphogenesis, organelle transport, and motility. The Rho family proteins are well characterized for their effects on the actin cytoskeleton, but increasing evidence indicates that they may also control microtubule (MT) dynamics. Here, we demonstrate that a novel Cdc42/Rac effector, X-p21-activated kinase (PAK)5, colocalizes and binds to both the actin and MT networks and that its subcellular localization is regulated during cell cycle progression. In transfected cells, X-PAK5 promotes the formation of stabilized MTs that are associated in bundles and interferes with MTs dynamics, slowing both the elongation and shrinkage rates and inducing long paused periods. X-PAK5 subcellular localization is regulated tightly, since coexpression with active Rac or Cdc42 induces its shuttling to actin-rich structures. Thus, X-PAK5 is a novel MT-associated protein that may communicate between the actin and MT networks during cellular responses to environmental conditions.