The clinical interest in farnesyltransferase inhibitors (FTIs) makes it important to understand how these compounds affect cellular processes involving farnesylated proteins. Mitotic abnormalities observed after treatment with FTIs have so far been attributed to defects in the farnesylation of the outer kinetochore proteins CENP-E and CENP-F, which are involved in chromosome congression and spindle assembly checkpoint signaling. Here we identify the cytoplasmic dynein adaptor Spindly as an additional component of the outer kinetochore that is modified by farnesyltransferase (FTase). We show that farnesylation of Spindly is essential for its localization, and thus for the proper localization of dynein and its cofactor dynactin, to prometaphase kinetochores and that Spindly kinetochore recruitment is more severely affected by FTase inhibition than kinetochore recruitment of CENP-E and CENP-F. Molecular replacement experiments show that both Spindly and CENP-E farnesylation are required for efficient chromosome congression. The identification of Spindly as a new mitotic substrate of FTase provides insight into the causes of the mitotic phenotypes observed with FTase inhibitors.
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http://dx.doi.org/10.1091/mbc.E14-11-1560 | DOI Listing |
Mol Biol Cell
December 2024
i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.
The microtubule motor cytoplasmic dynein-1 transports and positions various organelles, but the molecular basis of this functional diversity is not fully understood. Cargo adaptors of the Hook protein family recruit dynein to early endosomes (EE) in fungi and human cells by forming the FTS-Hook-FHIP (FHF) complex. By contrast, the Hook homolog ZYG-12 recruits dynein to the nuclear envelope (NE) in the meiotic gonad and mitotic early embryo by forming a Linker of Nucleoskeleton and Cytoskeleton (LINC) complex.
View Article and Find Full Text PDFElife
December 2024
Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China.
The structural integrity of the sperm is crucial for male fertility, defects in sperm head-tail linkage and flagellar axoneme are associated with acephalic spermatozoa syndrome (ASS) and the multiple morphological abnormalities of the sperm flagella (MMAF). Notably, impaired head-tail coupling apparatus (HTCA) often accompanies defects in the flagellum structure, however, the molecular mechanisms underlying this phenomenon remain elusive. Here, we identified an evolutionarily conserved coiled-coil domain-containing (CCDC) protein, CCDC113, and found the disruption of CCDC113 produced spermatozoa with disorganized sperm flagella and HTCA, which caused male infertility.
View Article and Find Full Text PDFNat Commun
December 2024
Cancer Metabolism and Microenvironment Program, NCI-Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.
Kidney360
December 2024
Division of Nephrology, Stead Family Department of Pediatrics, Carver College of Medicine, the University of Iowa.
Background: The p.Arg218Gln (R218Q) mutation in the inverted formin 2 (INF2) gene causes podocytopathy prone to focal segmental glomerulosclerosis (FSGS). This mutation disrupts the ability of INF2 to sequester DYNLL1, thus promoting dynein-mediated mistrafficking of the slit diaphragm protein, nephrin, to proteolytic pathways.
View Article and Find Full Text PDFbioRxiv
November 2024
i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.
The endoplasmic reticulum (ER) relies on the microtubule cytoskeleton for distribution and remodelling of its extended membrane network, but how microtubule-based motors contribute to ER organization remains unclear. Using biochemical and cell-based assays, we identify cerebellar degeneration-related protein 2 (CDR2) and its paralog CDR2-like (CDR2L), onconeural antigens with poorly understood functions, as ER adaptors for cytoplasmic dynein-1 (dynein). We demonstrate that CDR2 is recruited by the integral ER membrane protein kinectin (KTN1) and that double knockout of CDR2 and CDR2L enhances KTN1-dependent ER sheet stacking, reversal of which by exogenous CDR2 requires its dynein-binding CC1 box motif.
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