NDP kinase moves into developing primary cilia

• Published in: Cell motility and the cytoskeleton Vol. 59; no. 1; pp. 62 - 73
• Main Authors: Mitchell, Kimberly A. P., Gallagher, Betty C., Szabo, Gabor, de S. Otero, Angela
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01-09-2004
• Subjects: acetylated α-tubulin; Animals; Cilia - enzymology; Cilia - metabolism; Electrophoresis, Polyacrylamide Gel; Epithelial Cells - enzymology; Epithelial Cells - metabolism; Kidney - enzymology; Kidney - metabolism; length; Mice; NDP kinase; NIH 3T3 Cells; nm23; NM23 Nucleoside Diphosphate Kinases; Nucleoside-Diphosphate Kinase - metabolism; primary cilium; Tubulin - metabolism
• ISSN: 0886-1544; 1097-0169
• DOI: 10.1002/cm.20025

Inmunofluorescence staining of murine NIH3T3 fibroblasts grown at high density shows that conventional nucleoside diphosphate (NDP) kinases A and B localize to a sensory organelle, the primary cilium. Similar results are obtained with Xenopus A6 kidney epithelial cells, suggesting that NDP kinases are a universal component of the primary cilium. The translocation of NDP kinase into primary cilia depends on size, taking place only when cilia reach a critical length of 5–6 μm. In mature cilia, NDP kinases are distributed along the ciliary shaft in a punctate pattern that is distinct from the continuous staining observed with acetylated α‐tubulin, a ciliary marker and axonemal component. Isolation of a fraction enriched in primary cilia from A6 cells led to the finding that ciliary NDP kinase is enzymatically active, and is associated with the membrane and the matrix, but not the axoneme. In contrast, acetylated α‐tubulin is found in the axoneme and, to a lesser extent, in the membrane. Based on the tightly regulated translocation process and the subciliary distribution pattern of NDP kinase, we propose that it plays a role in the elongation and maintenance of primary cilia by its ability to regenerate the GTP utilized by ciliary microtubule turnover and transmembrane signaling. Cell Motil. Cytoskeleton 59:62–73, 2004. © 2004 Wiley‐Liss, Inc.