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Membrane bleb: A seesaw game of two small GTPases

Junichi Ikenouchi1,2,3, Kana Aoki1

  • 1a Department of Biology, Faculty of Sciences , Kyushu University , Fukuoka , Japan.

Small Gtpases
|June 18, 2016
PubMed

Insights

Membrane blebbing, essential for cell migration, is regulated by a cycle of Rnd3 and RhoA GTPases. This Rnd3-RhoA cycle controls the formation and retraction of cellular blebs.

Area of Science:

  • Cell biology
  • Molecular and cell biology

Background:

  • The plasma membrane interacts with the actin cytoskeleton.
  • Membrane blebs are spherical protrusions formed when the plasma membrane detaches from the actin cortex.
  • Blebs are crucial for cell migration but their molecular mechanisms are not fully understood.

Purpose of the Study:

  • To investigate the molecular mechanisms regulating membrane blebbing.
  • To identify key regulators of bleb formation and retraction.

Main Methods:

  • Investigated the roles of small GTPases Rnd3 and RhoA in membrane blebbing.
  • Examined the interaction between Rnd3, RhoA, RhoGAP, ROCK (Rho-associated protein kinase), and Ezrin during blebbing.

Main Results:

  • Rnd3 inhibits RhoA activity by activating RhoGAP in expanding blebs.
  • RhoA is activated at retracting membranes, removing Rnd3 via ROCK activity.
  • ROCK promotes actin cortex reassembly and bleb retraction by activating Ezrin.

Conclusions:

  • A Rnd3 and RhoA cycle is proposed as the core machinery for continuous membrane blebbing.
  • This cycle involves dynamic regulation of GTPase activity and interactions with downstream effectors.
Keywords:
ROCKRhoaRnd3actinblebbing

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