Differential roles of microtubule assembly and sliding in proplatelet formation by megakaryocytes
| العنوان: | Differential roles of microtubule assembly and sliding in proplatelet formation by megakaryocytes |
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| المؤلفون: | Jennifer L. Richardson, Harald Schulze, Eden Kahle, John H. Hartwig, Sunita R. Patel, Niels Galjart, Joseph E. Italiano, Ramesh A. Shivdasani, Ksenija Drabek |
| المصدر: | Blood. 106:4076-4085 |
| بيانات النشر: | American Society of Hematology, 2005. |
| سنة النشر: | 2005 |
| مصطلحات موضوعية: | Blood Platelets, Cytoplasm, Cellular differentiation, Immunology, Dynein, Biology, Microtubules, Biochemistry, Green fluorescent protein, Mice, Genes, Reporter, Microtubule, Animals, Dyneins, Cell Differentiation, Dynactin Complex, Cell Biology, Hematology, Microtubule sliding, Hematopoiesis, Cell biology, Protein Subunits, Dynactin, Kinesin, Megakaryocytes, Microtubule-Associated Proteins, Protein Binding |
| الوصف: | Megakaryocytes are terminally differentiated cells that, in their final hours, convert their cytoplasm into long, branched proplatelets, which remodel into blood platelets. Proplatelets elongate at an average rate of 0.85 microm/min in a microtubule-dependent process. Addition of rhodamine-tubulin to permeabilized proplatelets, immunofluorescence microscopy of the microtubule plus-end marker end-binding protein 3 (EB3), and fluorescence time-lapse microscopy of EB3-green fluorescent protein (GFP)-expressing megakaryocytes reveal that microtubules, organized as bipolar arrays, continuously polymerize throughout the proplatelet. In immature megakaryocytes lacking proplatelets, microtubule plus-ends initiate and grow by centrosomal nucleation at rates of 8.9 to 12.3 microm/min. In contrast, plus-end growth rates of microtubules within proplatelets are highly variable (1.5-23.5 microm/min) and are both slower and faster than those seen in immature cells. Despite the continuous assembly of microtubules, proplatelets continue to elongate when net microtubule assembly is arrested. One alternative mechanism for force generation is microtubule sliding. Triton X-100-permeabilized proplatelets containing dynein and its regulatory complex, dynactin, but not kinesin, elongate with the addition of adenosine triphosphate (ATP) at a rate of 0.65 microm/min. Retroviral expression in megakaryocytes of dynamitin (p50), which disrupts dynactin-dynein function, inhibits proplatelet elongation. We conclude that while continuous polymerization of microtubules is necessary to support the enlarging proplatelet mass, the sliding of overlapping microtubules is a vital component of proplatelet elongation. |
| تدمد: | 1528-0020 0006-4971 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b5f4128c8f39160156c417d85915b3ccTest https://doi.org/10.1182/blood-2005-06-2204Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....b5f4128c8f39160156c417d85915b3cc |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 15280020 00064971 |
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