Cell cycle-dependent morphological changes in the actin cytoskeleton induced by agents which elevate cyclic AMP

Area of Science:

• Cell Biology
• Biochemistry
• Cytoskeleton Dynamics

Background:

• Cyclic adenosine-5'-monophosphate (cAMP) is a crucial second messenger involved in various cellular processes.
• Fibroblast morphology and actin cytoskeleton organization are critical for cell function and response to stimuli.

Purpose of the Study:

• To investigate the morphological and cytoskeletal changes in Swiss 3T3 fibroblasts induced by agents that increase intracellular cAMP.
• To determine the cell cycle dependency of the cAMP-mediated arborisation response.

Main Methods:

• Treatment of sub-confluent Swiss 3T3 fibroblasts with agents that elevate intracellular cAMP.
• Analysis of actin filament organization using fluorescence microscopy.
• Assessment of cell cycle phase distribution and response timing after serum readdition.

Main Results:

• Agents increasing cAMP induced a highly arborised morphology in a proportion of fibroblasts.
• Actin filaments reorganized from stress fibers to a network within arborisations without changes in overall polymerization.
• The arborisation response was restricted to approximately 30% of cells in asynchronous cultures and occurred primarily in the G1 phase of the cell cycle.

Conclusions:

• Increased intracellular cAMP triggers significant actin cytoskeleton reorganization leading to fibroblast arborisation.
• The arborisation response is tightly regulated by the cell cycle, specifically occurring during the G1 phase.
• These findings highlight the role of cAMP signaling in modulating cell shape and cytoskeletal dynamics in a cell cycle-dependent manner.