Morphological changes in the Golgi complex correlate with actin cytoskeleton rearrangements

Area of Science:

• Cell Biology
• Cytoskeleton Dynamics
• Organelle Morphology

Background:

• The Golgi complex (GC) is a dynamic organelle involved in protein modification and transport.
• Actin cytoskeleton rearrangements are crucial for various cellular processes, including cell shape and motility.

Purpose of the Study:

• To investigate the morphological changes of the Golgi complex (GC) in response to actin cytoskeleton reorganization.
• To elucidate the role of phosphatidylinositide 3-kinase (PI3K) and actin microfilaments in GC morphology and function.

Main Methods:

• Immunofluorescence microscopy to visualize the Golgi complex using antibodies against resident proteins (giantin, mannosidase II, TGN-38).
• Stimulation of RBL-2H3 mast cells with epidermal growth factor (EGF), phorbol 12-myristate 13-acetate (PMA), and lysophosphatidic acid (LPA) to induce actin rearrangements.
• Treatment with Brefeldin A (BFA), cytochalasin D, jasplakinolide, wortmannin, and LY294002 to probe the involvement of actin and PI3K.

Main Results:

• Actin rearrangements induced by EGF/PMA and LPA caused specific Golgi complex morphological changes (reticular network and ring-shaped, respectively).
• Actin rearrangements occurred independently of the Golgi complex, as shown by Brefeldin A treatment.
• PMA-induced Golgi rearrangements were sensitive to actin-disrupting agents, while LPA-induced changes were not.
• Phosphatidylinositide 3-kinase (PI3K) inhibitors blocked PMA-induced Golgi morphological changes but not membrane ruffles.

Conclusions:

• The three-dimensional arrangement of actin microfilaments influences Golgi complex shape.
• Phosphatidylinositide 3-kinase (PI3K) regulates the association of the Golgi complex with actin microfilaments.
• Actin microfilaments are not essential for post-Golgi transport to the plasma membrane.