Related Experiment Video
Updated: Jun 23, 2025
Live Cell Imaging to Assess the Dynamics of Metaphase Timing and Cell Fate Following Mitotic Spindle Perturbations
Published on: September 20, 2019
Cell cycle-dependent centrosome clustering precedes proplatelet formation
Isabelle C Becker1,2, Adrian R Wilkie1,2, Emma Nikols1
1Vascular Biology Program, Boston Children's Hospital, 1 Blackfan Circle, Boston, MA 02115, USA.
Abstract:
Platelet-producing megakaryocytes (MKs) primarily reside in the bone marrow, where they duplicate their DNA content with each cell cycle resulting in polyploid cells with an intricate demarcation membrane system. While key elements of the cytoskeletal reorganizations during proplatelet formation have been identified, what initiates the release of platelets into vessel sinusoids remains largely elusive. Using a cell cycle indicator, we observed a unique phenomenon, during which amplified centrosomes in MKs underwent clustering following mitosis, closely followed by proplatelet formation, which exclusively occurred in G1 of interphase. Forced cell cycle arrest in G1 increased proplatelet formation not only in vitro but also in vivo following short-term starvation of mice. We identified that inhibition of the centrosomal protein kinesin family member C1 (KIFC1) impaired clustering and subsequent proplatelet formation, while KIFC1-deficient mice exhibited reduced platelet counts. In summary, we identified KIFC1- and cell cycle-mediated centrosome clustering as an important initiator of proplatelet formation from MKs.
Insights
Centrosome clustering, initiated by KIFC1 and the cell cycle, triggers proplatelet formation in megakaryocytes (MKs). This discovery sheds light on platelet production and could explain reduced platelet counts in KIFC1-deficient mice.
Area of Science:
- Hematology
- Cell Biology
- Molecular Biology
Background:
- Megakaryocytes (MKs) are polyploid cells in bone marrow responsible for platelet production.
- Proplatelet formation, the process of platelet release, is initiated by cytoskeletal changes but its trigger remains unclear.
- Understanding MKs and platelet biogenesis is crucial for treating thrombocytopenia.
Purpose of the Study:
- To elucidate the molecular mechanisms initiating proplatelet formation in megakaryocytes.
- To investigate the role of the cell cycle and centrosome behavior in platelet production.
- To identify key proteins involved in the early stages of platelet release.
Main Methods:
- Utilized cell cycle indicators to track megakaryocyte (MK) progression.
- Observed centrosome clustering following mitosis in MKs.
- Investigated the impact of KIFC1 inhibition on proplatelet formation in vitro and in vivo.
- Analyzed platelet counts in KIFC1-deficient mice.
Main Results:
- Observed that amplified centrosomes cluster post-mitosis, preceding proplatelet formation exclusively in G1 phase.
- Forced cell cycle arrest in G1 enhanced proplatelet formation both in vitro and in vivo.
- Inhibition of KIFC1 impaired centrosome clustering and subsequent proplatelet formation.
- KIFC1-deficient mice showed significantly reduced platelet counts.
Conclusions:
- KIFC1- and cell cycle-mediated centrosome clustering is a critical initiator of proplatelet formation.
- This mechanism provides new insights into megakaryocyte biology and platelet biogenesis.
- KIFC1 is essential for normal platelet production.
Related Concept Videos
02:25Centrosome Duplication
To ensure that each daughter cell receives a centrosome after cell division, centrosome duplication...
01:22Formation of the Platelet Plug
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...
01:13Centrioles and Centrosomes
Near the end of the prophase, also called late prophase or...
01:18Structure and Function of Platelets
Platelets are continually replenished, circulating in the bloodstream for 9-12 days before being removed by phagocytes, primarily in the spleen. A microliter of circulating blood contains between 150,000 and 450,000...
02:50Spindle Assembly
In most cells, centrosomes are the primary microtubule nucleation centers. In the centrosome-mediated pathway, the G2-prophase transition triggers centrosome maturation and increased microtubule nucleation. Progressive nucleation results in a...
01:23Microtubule Formation