Osteoclast stimulatory trasmembrane protein 1

Accession # NP_542452; Alternate nomenclature: Chromosome 20ORF123; C20Orf123, Zinc finger protein 334, Thyrotropin hormone releasing receptor like.

Skeletal homeostasis requires coordinated actions by bone forming osteoblastic and bone-resorptive osteoclastic activities. A decrease activity in bone resorption leads to sclerotic bone as often seen in osteopetrosis and excessive bone resorption is central to osteoporosis, tumor metastasis, arthritis, periodontal diseases and prosthetic joint implant loosening. Controlling the osteoclastic activity in multinucleated osteoclasts mononuclear hematopoitic cells will be important in understanding many pathological conditions related to bone diseases. Multinucleated osteoclasts are formed by fusion of mononuclear, heomatopoitic cells of monocyte/macrophage lineage and these cells respond to signals form colony-stimulating factor (C-SF, M-CSF) and express RANK, the receptor for the TNF superfamily member RANKL that includes TRANCE, OPGL and ODF (1). The RANKL and C-SF-1 are supplied by the obteoblasts and are required for differentiation of osteoclasts. Upon differentiation there is a gene highly up-regulated in osteoclasts that has significant homology in the extended C-terminal region with Dc-STOMP protein. The DC-STAMP is a multipass membrane protein that was originally identified in gene expression experiment I in dendritic cells.  Blocking of DC-STAMP activity inhibited the osteoclast differentiation and overexpressing DC-STAMP increase osteoclast differentiation (2).  DC-STAMP cells are unable to induce cell fusion but they fuse with DC-STAMP positive cells giving early mechanistic indication that the trans-membrane protein may be involved in cell-cell fusion (3). The ligand for DC-STAMP is not known but this family of protein was found in many other species.

The conserved domain database list several dozen DC-STAMP consensus-containing proteins including mouse, human and monkey DC-STAMP. One of many DC-STMP is recently characterized in osteoclasts named Osteoclast stimulatory trans-membrane protein (OC-STAMP) which has a significant role in pre-osteoclast fusion (4). The OC-STAMP is induced by RANKL and it inhibits multinucleated osteoclast formation when blocked by SiRNA or by antibody and over expression of OC-STAMP promote osteoclast differentiation (4).  The gene for OC-STAMP lies on chromosome 20q13.12 and transcribe a protein with 566 aa containing 6 TMD having an extended C terminal end. 

  The OC-STAMP-selective antibodies were generated against peptide taken form with in the second intra-cytoplasmic domain. The OC-STAMP-selective antibodies are affinity purified over immobilized antigen based affinity chromatography which yielded high affinity epitope-specific antibodies.  The OC-STAMP antibodies label a protein of approximately 72kDa on Western blot using Western blot positive control for OC-STAMP (PC-OC-STAMP).  OC-STAMP-selective antibodies are also available in FITC conjugated preparations for confocal and immunocytochemical analyses.  FabGennix Inc. will also conjugate antibodies to many other fluorescent probes upon request at a nominal charge.  Limited quantities of antigenic blocking peptide and western blot positive controls are also available (inquire before ordering).   FabGennix Inc. has an inventory of more than 1100 well characterized antibodies for research and diagnostic applications, for a complete listing please visit www.FabGennix.com. 

Imunogen:      Synthetic peptide taken from human OC-STAMP protein taken from with in the second intracellular loop of OC-STAMP. The peptide was conserved in several other species.  The selected peptide was post-synthetically modified to achieve highest antigenicty before coupling to carrier protein using hetero bifunctional cross linker for immunogen preparation.                

CoConcentration:   Affinity purified OC-STAMP-101AP antibody (0.59-0.63mg/ml) was stabilized in antibody stabilization buffer for long-term storage.

AaApplications:     OC-STAMP-101AP antibody was tested in ELISA and western blotting applications at 1:500 dilution using PC-OC-STAMP samples.  Antibody dilutions for this antibody is for reference only, investigators are expected to determine the optimal conditions.  Application of this antibody in other protocols has not yet tested. WB: > 1:500; IMM & i.p pull-down assays: n.d; IHC n.d.  Investigators using this antibody in protocols other than listed above can request a complimentary sample of this antibody.                      

     Protocols:     Standard protocol for various applications (WB, IMM, IHC) of this antibody can be obtained upon request. The specification sheet for OC-STAMP antibody will be supplied with each product.  FabGennix Inc., strongly recommends investigators to optimize conditions for use of this antibody in their laboratories.  

For research use only, not for diagnostic or therapeutic use.