Previously, we showed PAK-PIX-GIT targets and regulates focal adhesions; here, we uncover a different function for the complex at the centrosome. Active PAK1 is particularly evident in mitosis and phosphorylates the centrosomal adaptor GIT1 on serine 517. Interestingly, direct centrosome targeting activates the kinase via a process not requiring Rho GTPases; excision of the centrosome prevents this activation. Once activated, PAK1 dissociates from PIX/GIT but can bind to and phosphorylate the important centrosomal kinase Aurora-A. PAK1 promotes phosphorylation of Aurora-A on Thr288 and Ser342, which are key sites for kinase activation in mitosis. In vivo PAK activation causes an accumulation of activated Aurora-A; conversely, when betaPIX is depleted or PAK is inhibited, there is a delay in centrosome maturation. These observations may underlie reported effects of active PAK on cells, including histone H3 phosphorylation, alterations in centrosome number, and progression through mitosis.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.molcel.2005.08.035 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Revealing the dance of NLRP3: spatiotemporal patterns in inflammasome activation.
Immunometabolism (Cobham)
January 2025
Institute for Systems Biology, Seattle, WA, USA.
The nucleotide-binding domain, leucine-rich repeat, and pyrin domain containing-protein 3 (NLRP3) inflammasome is a multiprotein complex that plays a critical role in the innate immune response to both infections and sterile stressors. Dysregulated NLRP3 activation has been implicated in a variety of autoimmune and inflammatory diseases, including cryopyrin-associated periodic fever syndromes, diabetes, atherosclerosis, Alzheimer's disease, inflammatory bowel disease, and cancer. Consequently, fine-tuning NLRP3 activity holds significant therapeutic potential.
View Article and Find Full Text PDFSYS-1/beta-catenin inheritance and regulation by Wnt-signaling during asymmetric cell division.
Mol Biol Cell
January 2025
Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA.
Asymmetric cell division (ACD) allows daughter cells of a polarized mother to acquire different developmental fates. In , the Wnt/β-catenin Asymmetry (WβA) pathway regulates many embryonic and larval ACDs; here, a Wnt gradient induces an asymmetric distribution of Wnt signaling components within the dividing mother cell. One terminal nuclear effector of the WβA pathway is the transcriptional activator SYS-1/β-catenin.
View Article and Find Full Text PDFHN1 Functions in Protein Synthesis Regulation via mTOR-RPS6 Axis and Maintains Nucleolar Integrity.
Cell Prolif
January 2025
Faculty of Engineering, Department of Bioengineering, Cancer Biology Laboratory, Ege University, Bornova, Izmir, Turkey.
Haematological and Neurological Expressed 1 (HN1) is an oncogene for various cancers and previously has been linked with centrosome clustering and cell cycle pathways. Moreover, HN1 has recently been reported to activate mTOR signalling, which is the regulator of ribosome biogenesis and maintenance. We explored the role of HN1 in mTOR signalling through various gain- and loss-of-function experiments using biochemical approaches in different cell lines.
View Article and Find Full Text PDFSSNA-1 is a fibrillar protein localized at the area where dynamic microtubule remodeling occurs including centrosomes. Despite the important activities of SSNA1 to microtubules such as nucleation, co-polymerization, and lattice sharing microtubule branching, the underlying molecular mechanism have remained unclear due to a lack of structural information. Here, we determined the cryo-EM structure of SSNA-1 at 4.
View Article and Find Full Text PDFOTUD6B regulates KIFC1-dependent centrosome clustering and breast cancer cell survival.
EMBO Rep
January 2025
Cellular and Molecular Physiology, Institute of Systems Molecular and Integrative Biology, University of Liverpool, Crown St, Liverpool, L69 3BX, UK.
Cancer cells often display centrosome amplification, requiring the kinesin KIFC1/HSET for centrosome clustering to prevent multipolar spindles and cell death. In parallel siRNA screens of deubiquitinase enzymes, we identify OTUD6B as a positive regulator of KIFC1 expression that is required for centrosome clustering in triple-negative breast cancer (TNBC) cells. OTUD6B can localise to centrosomes and the mitotic spindle and interacts with KIFC1.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!