Related Experiment Video

Updated: Aug 14, 2026

A RANKL-based Osteoclast Culture Assay of Mouse Bone Marrow to Investigate the Role of mTORC1 in Osteoclast Formation
09:37

A RANKL-based Osteoclast Culture Assay of Mouse Bone Marrow to Investigate the Role of mTORC1 in Osteoclast Formation

Published on: March 15, 2018

Abnormal localisation and hyperclustering of (alpha)(V)(beta)(3) integrins and associated proteins in Src-deficient

P T Lakkakorpi1, I Nakamura, M Young

  • 1Department of Bone Biology and Osteoporosis Research, Merck Research Laboratories, West Point, Pennsylvania 19486, USA.

Journal of Cell Science
|December 12, 2000
PubMed

Insights

The non-receptor tyrosine kinase Src is crucial for osteoclast function and bone resorption. Src kinase activity regulates the proper localization of alpha(v)beta(3) integrins and downstream signaling molecules during osteoclast resorption.

Area of Science:

  • Cell Biology
  • Biochemistry
  • Skeletal Biology

Background:

  • The non-receptor tyrosine kinase Src is essential for osteoclast function.
  • Alpha(v)beta(3) integrin engagement in osteoclasts activates PYK2 and p130(Cas) in a Src-dependent manner.
  • Osteoclasts are critical for bone resorption.

Purpose of the Study:

  • To investigate the role of c-Src in the alpha(v)beta(3) integrin-dependent recruitment of signaling and cytoskeletal molecules in osteoclasts during bone resorption.

Main Methods:

  • Utilized prefusion osteoclasts (pOCs) from Src(-/-) and wild-type mice.
  • Analyzed alpha(v)beta(3) integrin expression, ligand binding, adhesion, and spreading.
  • Examined the organization of microfilament proteins (F-actin, vinculin, paxillin), PYK2, and p130(Cas) in the sealing zone.
  • Investigated alpha(v)beta(3) integrin clustering in Src-deficient osteoclasts.
  • Used the tyrosine kinase inhibitor tyrphostin A9 on normal osteoclasts.

Main Results:

  • Src(-/-) pOCs exhibited reduced adhesion and spreading.
  • Defective organization of microfilament proteins and signaling molecules (PYK2, p130(Cas)) in the sealing zone of Src(-/-) osteoclasts.
  • Src deficiency led to hyperclustering of alpha(v)beta(3) integrins with cytoskeletal and signaling proteins.
  • Tyrphostin A9 treatment mimicked the hyperclustering phenotype observed in Src-deficient osteoclasts and inhibited actin ring formation and bone resorption.

Conclusions:

  • Src kinase activity is essential for the correct localization of alpha(v)beta(3) integrins within osteoclasts.
  • Src regulates the recruitment of downstream signaling and cytoskeletal effectors to specific cellular compartments during bone resorption.
  • These findings highlight Src's critical role in orchestrating osteoclast adhesion, cytoskeletal organization, and resorptive function.

More Related Videos

Isolation, Purification, and Differentiation of Osteoclast Precursors from Rat Bone Marrow11:11

Isolation, Purification, and Differentiation of Osteoclast Precursors from Rat Bone Marrow

Published on: May 19, 2019

Skeletal Phenotype Analysis of a Conditional Stat3 Deletion Mouse Model08:42

Skeletal Phenotype Analysis of a Conditional Stat3 Deletion Mouse Model

Published on: July 3, 2020

Related Concept Videos

Enzyme-linked Receptors01:00

Enzyme-linked Receptors

Enzyme-linked receptors are proteins that act as both receptor and enzyme, activating multiple intracellular signals. This is a large group of receptors that include the receptor tyrosine kinase (RTK) family. Many growth factors and hormones bind to and activate the RTKs.
Neurotrophin (NT) receptors are a family of RTKs, including trkA, trkB, and trkC (tropomyosin-related kinase) receptors. TrkA is specific for nerve growth factor (NGF), neurotrophin-6, and neurotrophin-7. TrkB binds...
Receptor Downregulation in MVBs01:15

Receptor Downregulation in MVBs

Multivesicular bodies (MVBs) are mature endosomes that sort ubiquitinated proteins and then fuse with lysosomes to degrade the sorted proteins. Epidermal growth factor (EGF) and its receptor (EGFR) form a complex that can be internalized through endocytosis, sorted into an MVB, and later degraded.
The EGFR can initiate signaling pathways that  lead to cell proliferation, migration, and differentiation. Overexpression of EGFR  stimulates cells to proliferate. Excessive  EGFR activation may...
Receptor Tyrosine Kinases01:26

Receptor Tyrosine Kinases

Receptor tyrosine kinases or RTKs are membrane-bound receptors that phosphorylate specific tyrosine on protein substrates. RTKs regulate cellular growth, differentiation, survival, and migration. They contain an extracellular ligand binding domain, a transmembrane domain, and a cytosolic tail with intrinsic kinase activity. Several extracellular signaling molecules activate RTKs in one or more ways and relay the signal downstream. Ligands such as platelet-derived growth factor (PDGF) or...
Integrins01:10

Integrins

Animal and protozoan cells do not have cell walls to help maintain shape and provide structural stability. Instead, these eukaryotic cells secrete a sticky mass of carbohydrates and proteins into the spaces between adjacent cells. This network of proteins and molecules is called an extracellular matrix or ECM.
Some ECM proteins assemble into a basement membrane to which the remaining components adhere. Proteoglycans typically form the bulk of the ECM while fibrous proteins, like collagen,...
Activation of Integrins01:15

Activation of Integrins

Integrins bind ligands and transmit information from outside the cell to inside or vice-versa through an "outside-in signaling" or "inside-out signaling."
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.
Intracellular Signaling Affects Focal Adhesions01:17

Intracellular Signaling Affects Focal Adhesions

Integrins act both as extracellular input receivers and as intracellular processing activators. As their name suggests, integrins are entirely integrated into the membrane structure. Their hydrophobic membrane-spanning regions interact with the phospholipid bilayer's hydrophobic region. These membrane receptors provide extracellular attachment sites for effectors like hormones and growth factors. They activate intracellular response cascades when their effectors are bound and active.
Some...