Related Experiment Video

Updated: Aug 25, 2026

Acquisition of High-Quality Digital Video of Drosophila Larval and Adult Behaviors from a Lateral Perspective
07:00

Acquisition of High-Quality Digital Video of Drosophila Larval and Adult Behaviors from a Lateral Perspective

Published on: October 4, 2014

Role of myosin-II phosphorylation in V12Cdc42-mediated disruption of Drosophila cellularization

J M Crawford1, Z Su, O Varlamova

  • 1Department of Cell Biology, Duke University Medical Center, Durham, NC 27708-1000, USA.

European Journal of Cell Biology
|April 27, 2001
PubMed

Insights

Constitutively active Cdc42 disrupts the actomyosin cytoskeleton. While p21-activated kinase (PAK) concentrates at these sites and phosphorylates myosin-II, it does not cause cytoskeletal disruption, suggesting RLC phosphorylation is not the cause.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • The actomyosin cytoskeleton is crucial for cellular processes like cellularization.
  • Small GTPases, such as Cdc42, regulate cytoskeletal dynamics.
  • p21-activated kinase (PAK) is a downstream effector of Cdc42.

Purpose of the Study:

  • To investigate the role of Drosophila PAK in V12Cdc42-induced actomyosin disruption during cellularization.
  • To determine if PAK-mediated phosphorylation of myosin-II regulatory light chain (RLC) contributes to cytoskeletal disruption.

Main Methods:

  • Microinjection of V12Cdc42 into Drosophila cells.
  • Immunofluorescence microscopy to observe cytoskeletal organization and protein localization.
  • In vitro biochemical assays to assess PAK kinase activity and RLC phosphorylation.

Main Results:

  • V12Cdc42 injection disrupts the actomyosin cytoskeleton.
  • Drosophila PAK localizes to sites of V12Cdc42-induced disruption and phosphorylates RLC on Ser21.
  • Activated PAK alone does not disrupt the actomyosin cytoskeleton but increases RLC phosphorylation.

Conclusions:

  • Increased RLC phosphorylation by PAK does not appear to be the primary cause of V12Cdc42-induced actomyosin disruption.
  • PAK's role in regulating myosin-II activity may be distinct from its effect on cytoskeletal integrity during cellularization.

More Related Videos

A Cell-based Assay to Investigate Non-muscle Myosin II Contractility via the Folded-gastrulation Signaling Pathway in Drosophila S2R+ Cells07:15

A Cell-based Assay to Investigate Non-muscle Myosin II Contractility via the Folded-gastrulation Signaling Pathway in Drosophila S2R+ Cells

Published on: August 19, 2018

Optogenetic Inhibition of Rho1-Mediated Actomyosin Contractility Coupled with Measurement of Epithelial Tension in Drosophila Embryos12:35

Optogenetic Inhibition of Rho1-Mediated Actomyosin Contractility Coupled with Measurement of Epithelial Tension in Drosophila Embryos

Published on: April 14, 2023

Related Concept Videos

Actin Polymerization and Cell Motility01:13

Actin Polymerization and Cell Motility

Actin is a family of globular proteins that are highly abundant in eukaryotic cells. It makes up approximately 1-5% of total cell protein concentration. Actin monomers polymerize to form a complex network of polarized filaments, the actin cytoskeleton, that plays a crucial role in many cellular processes, including cell motility, division, endocytosis, and metastasis of cancer cells.
Actin cytoskeleton dynamics can produce pushing, pulling, and resistance forces that help the cell to migrate.
Mechanism of Filopodia Formation01:39

Mechanism of Filopodia Formation

Filopodia are thin, actin-rich cellular protrusions that play an important role in many fundamental cellular functions. They vary in their occurrence, length, and positioning in different cell types, suggesting their diverse roles.
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
Mechanism of Lamellipodia Formation01:31

Mechanism of Lamellipodia Formation

Cells migrating in response to external stimuli form lamellipodia, which are thin membrane protrusions supported by a mesh of linked, branched, or unbranched actin filaments. These actin filaments interact with myosin motor proteins, creating the dynamic actomyosin complex within the cytoskeleton. Contractility, or the ability to generate contractile stress, is inherent to the actomyosin complex. It helps cells detect the stiffness of the surrounding ECM and exert contractile force for...
Cell Motility through Blebbing01:16

Cell Motility through Blebbing

Blebs are a type of membrane protrusion formed by the internal hydrostatic pressure of the cytoplasm. Blebs are observed in several cell types, including fibroblasts, immune cells, and single-celled organisms like the amoeba. The primary function of blebs is cell locomotion and apoptosis, but they are also found during necrosis and cell division. The life cycle of a bleb comprises an initiation phase followed by the expansion and retraction phases.
Blebbing Through the Matrix
In multicellular...
Role of Myosin in Cell Migration01:18

Role of Myosin in Cell Migration

Myosins are multimeric motor proteins involved in various cellular processes such as migration, adhesion, and proliferation. Myosin II is the most common type in animal cells, which binds and cross-links actin filaments.
Myosin II  is a hexamer comprising two heavy chains with globular heads and coiled-coil tails, two regulatory light chains, and two essential light chains. The ATPase sites on the myosin heads hydrolyze ATP, and the released phosphate generates the force for contraction. It is...
Disassembly of Intermediate Filaments01:35

Disassembly of Intermediate Filaments

Intermediate filaments (IFs) do not undergo spontaneous disassembly. Enzymes, kinases, and phosphatases add and remove phosphates from specific sites to regulate their disassembly. The IF concentration in the cytoplasm also regulates the disassembly. If the concentration crosses a threshold, it activates the protein kinases in the vicinity, allowing the phosphorylation of IFs.
Keratin proteins, found at the cell periphery near cell junctions, undergo a cycle of assembly and disassembly. In Type...