Cellular responses to gravity: extracellular, intracellular and in-between

Area of Science:

• Cell biology
• Gravitational biology
• Biophysics

Background:

• Cellular responses to gravity (inertial effects) are increasingly understood, particularly extracellular effects on small cells and intracellular effects on eukaryotic gravisensing cells.
• The response mechanisms of cells not solely governed by extracellular physics (e.g., prokaryotes) or lacking obvious mechanical gravity sensors (e.g., some plant and animal cells) remain unclear.
• This 'in-between' class of cells requires investigation into combined intracellular and extracellular gravity-dependent processes.

Purpose of the Study:

• To elucidate the gravity response mechanisms of 'in-between' cell classes.
• To identify experimentally measurable variables relevant to cellular responses to modified inertial forces.
• To compare cellular forces with approximately 1 x g inertial forces in the context of cytoskeletal action and symmetry-breaking pathways.

Main Methods:

• Comparative analysis of cellular forces generated or responded to by various cell types.
• Investigation of cytoskeletal action and symmetry-breaking pathways in response to gravity.
• Examination of intracellular and extracellular gravity-dependent processes.

Main Results:

• Established understanding of extracellular effects on small cells and intracellular effects on eukaryotic gravisensing cells.
• Identified a gap in understanding for 'in-between' cell classes lacking specialized mechanical sensors.
• Proposed a framework for studying these cells via combined intracellular/extracellular gravity-dependent processes.

Conclusions:

• Further research is essential to understand the gravity response of 'in-between' cell classes.
• A combined approach considering intracellular and extracellular gravity-dependent processes is necessary.
• Cytoskeletal action and symmetry-breaking pathways are key areas for investigating cellular responses to inertial forces.