Plasma Membrane Blebbing Is Controlled by Subcellular Distribution of Vimentin Intermediate Filaments

Area of Science:

• Cell Biology
• Biophysics
• Biochemistry

Background:

• Amoeboid cell motility, crucial for various cell types including leukocytes and tumor cells, relies on plasma membrane bleb formation.
• Cellular heterogeneity exists in bleb formation propensity, even within the same cell culture under identical conditions.

Purpose of the Study:

• To investigate the role of vimentin intermediate filaments (VIFs) in regulating heterogeneous membrane blebbing in HT1080 fibrosarcoma cells.
• To elucidate the functional significance of VIF distribution in controlling cell migration and mitotic processes.

Main Methods:

• Experimental induction of membrane blebbing in HT1080 fibrosarcoma cells.
• Manipulation of VIF organization through various experimental approaches.
• Microscopic analysis of VIF distribution relative to blebbing activity in interphase and mitotic cells.
• Vimentin gene silencing and peripheral VIF displacement experiments.

Main Results:

• Blebbing activity is inversely correlated with VIF density at the cell periphery; edges with fewer VIFs exhibit higher blebbing.
• VIF-rich cell periphery regions show reduced blebbing activity.
• Downregulation of vimentin or its displacement from the cell edge enhances blebbing, even in previously resistant cells.

Conclusions:

• Vimentin intermediate filaments play a critical regulatory role in non-apoptotic plasma membrane blebbing.
• VIF organization directly influences the propensity for amoeboid cell migration and mitosis-associated blebbing.
• This study uncovers a novel function of VIFs in controlling cell motility and division.