Cell Signaling Technology

Product Pathways - Lymphocyte Signaling

CD45 (136-4B5) Mouse mAb #3575

Applications Reactivity Sensitivity MW (kDa) Isotype
IHC-P H Endogenous 180 to 240 Mouse IgG1

Applications Key:  IHC-P=Immunohistochemistry (Paraffin)
Reactivity Key:  H=Human
Species cross-reactivity is determined by western blot. Species enclosed in parentheses are predicted to react based on 100% sequence homology.

Protocols

Specificity / Sensitivity

CD45 (136-4B5) Mouse mAb detects endogenous levels of total CD45 protein.

Source / Purification

Monoclonal antibody is produced by immunizing BALB/c mice with stimulated human leukocytes.

IHC-P (paraffin)

IHC-P (paraffin)

Immunohistochemical analysis of paraffin-embedded human tonsil using CD45 (136-4B5) Mouse mAb.

Background

The protein phosphatase (PTP) receptor CD45 is a type I transmembrane protein comprised of a pair of intracellular tyrosine phosphatase domains and a variable extracellular domain generated by alternative splicing (1). The catalytic activity of CD45 is a function of the first phosphatase domain (D1) while the second phosphatase domain (D2) may interact with and stabilize the first domain, or recruit/bind substrates (2,3). CD45 interacts directly with antigen receptor complex proteins or activates Src family kinases involved in the regulation of T- and B-cell antigen receptor signaling (1). Specifically, CD45 dephosphorylates Src-family kinases Lck and Fyn at their conserved negative regulatory carboxy-terminal tyrosine residues and upregulates kinase activity. Conversely, studies indicate that CD45 can also inhibit Lck and Fyn by dephosphorylating their positive regulatory autophosphorylation site. CD45 appears to be both a positive and a negative regulator that conducts signals depending on specific stimuli and cell type (1). Human leukocytes including lymphocytes, eosinophils, monocytes, basophils and neutrophils express CD45, while erythrocytes and platelets are negative for CD45 expression (4).

  1. Huntington, N.D. and Tarlington, D.M. (2004) Immunol. Lett. 94, 167-174.
  2. Felberg, J. and Johnson, P. (2000) Biochem. Biophys. Res. Commun. 271, 292-298.
  3. Kashio, N. et al. (1998) J. Biol. Chem. 273, 33856-33863.
  4. Wang, Y. and Johnson, P. (2005) J. Biol. Chem. 280, 14318-14324.

Application References

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Companion Products

For Research Use Only. Not For Use In Diagnostic Procedures.

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