Distinct functional effects for dynamin 3 during megakaryocytopoiesis

Area of Science:

• Cell Biology
• Hematopoiesis
• Protein Function

Background:

• Dynamin 3 (DNM3) is a motor protein involved in membrane dynamics.
• Emerging evidence suggests a role for DNM3 in megakaryocyte (MK) development.

Purpose of the Study:

• To investigate the functional role of DNM3 in megakaryocytopoiesis.
• To elucidate DNM3's contribution to MK progenitor amplification, cytoplasmic growth, and demarcation membrane system (DMS) formation.

Main Methods:

• Short hairpin RNAs (shRNAs) were used to knock down DNM3 expression in developing MKs.
• Quantification of progenitor cells (CFU-MKs), nucleated cells, and MK surface markers (CD41, CD61).
• Styryl membrane dye and immunofluorescence were used to assess DMS formation and protein co-localization (DNM3, nonmuscle myosin IIA/MYH9).

Main Results:

• DNM3 knockdown significantly inhibited MK progenitor amplification, reducing CFU-MKs, total nucleated cells, and CD41/CD61 positive MKs.
• DNM3 co-localized with the DMS, and its knockdown precluded DMS formation in terminally differentiated MKs.
• DNM3 depletion led to smaller MKs and impaired cytoplasmic enlargement, with DNM3 and actin shown to bind MYH9.

Conclusions:

• DNM3 plays a critical role in MK progenitor amplification.
• DNM3 is essential for cytoplasmic enlargement and the formation of the DMS during megakaryopoiesis.
• DNM3 interacts with MYH9, suggesting a mechanism for its role in MK development.