Spastin is an AAA (ATPase associated with diverse cellular activities) protein with microtubule (MT)-severing activity. The spastin-encoding gene was identified as the most often mutated gene in the human neurodegenerative disease hereditary spastic paraplegia. Although the structure of the AAA domain of spastin has been determined, the mechanism by which spastin severs MTs remains elusive. Here, we studied the MT-binding and nucleotide-binding properties of spastin, as well as their interplay. The results suggest that ATP-bound spastin interacts strongly and cooperatively with MTs; this interaction stimulates ATP hydrolysis by spastin. After ATP hydrolysis, spastin dissociates from MTs, and then exchanges ADP for ATP in solution for the next round of work. In particular, spastin in the ternary complex of MT-spastin-ATP is the most cooperative state during the working cycle, and is probably the force-generating state that is responsible for MT severing. The results presented in this study establish the nucleotide cycle of spastin in correlation with its MT-binding properties, and provide a biochemical framework for further studies of the working mechanism of spastin.
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http://dx.doi.org/10.1111/febs.12385 | DOI Listing |
Eur J Neurol
January 2025
Service de Génétique Médicale, CHU Bordeaux, Bordeaux, France.
Purpose: Heterozygous pathogenic variants in SPAST are known to cause Hereditary Spastic Paraplegia 4 (SPG4), the most common form of HSP, characterized by progressive bilateral lower limbs spasticity with frequent sphincter disorders. However, there are very few descriptions in the literature of patients carrying biallelic variants in SPAST.
Methods: Targeted Sanger sequencing, panel sequencing and exome sequencing were used to identify the genetic causes in 9 patients from 6 unrelated families with symptoms of HSP or infantile neurodegenerative disorder.
Biochim Biophys Acta Mol Cell Res
December 2024
Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China. Electronic address:
Microtubule-severing enzymes such as spastin, katanin, and fidgetin, characterized by their AAA ATPase domains, are pivotal in modulating microtubule dynamics and behavior across various cellular processes. While spastin and katanin are recognized for their predominant and robust severing of stable microtubules, thereby enhancing microtubule turnover, fidgetin exhibits comparatively weaker severing activity and selectively targets labile microtubules. The interplay among these enzymes and their mutual regulatory mechanisms remains inadequately understood.
View Article and Find Full Text PDFNan Fang Yi Ke Da Xue Xue Bao
November 2024
Department of Reproductive Medicine, Jinling Clinical Medical College, Nanjing University of Chinese Medicine, Nanjng 210002, China.
EMBO Rep
December 2024
Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland.
The early branching eukaryote Naegleria gruberi can transform transiently from an amoeboid life form lacking centrioles and flagella to a flagellate life form where these elements are present, followed by reversion to the amoeboid state. The mechanisms imparting elimination of axonemes and centrioles during this reversion process are not known. Here, we uncover that flagella primarily fold onto the cell surface and fuse within milliseconds with the plasma membrane.
View Article and Find Full Text PDFMov Disord
November 2024
Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA.
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