Pericentrosomal Redistribution of the Endoplasmic Reticulum Ensures Organelle Symmetric Inheritance and Mitotic...

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• Symmetric cell division requires equal distribution of cellular components, but organelle segregation mechanisms are not fully understood.
• The endoplasmic reticulum (ER) is a dynamic organelle involved in cellular state sensing and organelle coordination.
• Understanding ER dynamics during mitosis is crucial for comprehending cell division fidelity.

Purpose of the Study:

• To elucidate the mechanisms of endoplasmic reticulum (ER) reorganization during early mitosis.
• To investigate the role of Reticulon 4 (RTN4) in ER segregation and its impact on mitotic progression.
• To uncover how ER remodeling contributes to the symmetric inheritance of organelles.

Main Methods:

• Investigated ER structural changes upon mitotic entry using microscopy.
• Utilized biochemical assays to study the phosphorylation of Reticulon 4 (RTN4) by cyclin-dependent kinase 1 (CDK1).
• Examined the interaction between RTN4 and Rab11 and the role of dynein in ER reorganization.

Main Results:

• Observed a reverse redistribution of the ER during mitosis, with tubular ER accumulating pericentrosomally and sheet ER moving to the cell periphery.
• Demonstrated that CDK1-mediated phosphorylation of RTN4 promotes its interaction with Rab11.
• Showed that RTN4 enrichment around centrosomes, dependent on dynein, drives pericentrosomal ER tubularization.

Conclusions:

• RTN4-mediated ER reorganization during early mitosis ensures symmetric ER distribution and inheritance.
• Mitotic ER remodeling contributes to the symmetric segregation of other organelles, maintaining mitotic fidelity.
• This study reveals a novel mechanism for ER symmetry remodeling essential for organelle inheritance and cell division.