How Do Bone Cells Secrete Proteins?

  • Haibo ZhaoEmail author
  • Yuji Ito
  • Jean Chappel
  • Norma Andrews
  • F. Patrick Ross
  • Steven L. Teitelbaum
Conference paper
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 658)


Osteoclasts (OCs), which are the exclusive bone resorbing cells, degrade skeletal matrix by forming an intimate relationship with the bone surface. Thus, when OCs attach to bone, they produce an actin-rich sealing zone representing a gasket-like structure, which isolates the resorptive milieu from the general extracellular space. This “resorptive microenvironment” contains a ruffled border, the unique bone-degrading organelle of the OC, which consists of a complex, villous-like organization of the plasma membrane. This structure appears only in resorbing cells and is the product of signals derived from the bone matrix. These signals polarize as yet undefined acidified vesicles containing the OC vacuolar H+ATPase towards the bone-apposed plasma membrane, into which they insert, thereby increasing its complexity. The ruffled border is thus the most definitive marker of the resorbing osteoclast.


Osteoclasts Exocytosis Ruffled border 


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Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Haibo Zhao
    • 1
    Email author
  • Yuji Ito
    • 1
  • Jean Chappel
    • 1
  • Norma Andrews
    • 2
  • F. Patrick Ross
    • 1
  • Steven L. Teitelbaum
    • 1
  1. 1.Pathology and ImmunologyWashington University School of MedicineSt. LouisUSA
  2. 2.Section of microbial PathogenesisYale University School of MedicineNew HavenUSA

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