Catalog # CP4701

Crk II (Tyr-221), phospho-specific Antibody

Rabbit Polyclonal

Application / Dilution

Size 100 μl

Species Reactivity Hu, Rt, Ms, Ck, F

MW 40 kDa



The Crk family of adaptor proteins (Crk I, Crk II and CrkL) are Src Homology 2 (SH2) and Src Homology 3 (SH3) domain-containing proteins that form protein complexes important for transmiting signals downstream of tyrosine kinases. Both Crk II and CrkL are composed of a single SH2 domain, followed by two tandem SH3 domains. Crk II is also alternatively spliced to a minor product, Crk I, which is structurally and functionally more similar to the v-Crk oncogene. Both Crk II and CrkL are ubiquitously expressed and their SH domains are highly homologous, however both are required for mouse development and have distinct non-overlapping phenotypes in knockout mice. Phosphorylation may be important for regulating Crk activity. Crk II Tyr-221 (CrkL Tyr-207) phosphorylation is a negative regulatory site, while Crk Tyr-251 phosphorylation in the SH3 domain is a positive regulatory site. EGF stimulation induces phosphorylation of Tyr-251, which increases binding of Crk to the SH2 domain of Abl, and promotes transactivation of Abl.


Sriram, G. et al. (2011) Oncogene 30(46):4645.
Feller, S.M. & Lewitzky, M. (2006) Curr. Pharm. Des. 12(5):529.
Feller, S.M. (2001) Oncogene. 20(44):6348.

Western blot of human K562 cells stimulated with pervanadate (1 mM) for 30 min. (lanes 1-4). The blot was treated with alkaline phosphatase to dephosphorylate Crk II (lanes 2 & 4), then the blot was probed with mouse monoclonal Crk II (C-terminal region) CM3321 (lanes 1 & 2) and Crk II (Tyr-221) phospho-specific CP4701 (lanes 3 & 4).

Phospho-Crk (Tyr-221) synthetic peptide (coupled to KLH) corresponding to amino acid residues surrounding Tyr-221 in human Crk II. This peptide sequence is well conserved in mouse and rat Crk II, and has 40% homology with the conserved site in CrkL (Tyr-207). The site is not found in Crk I.

*For more information, see UniProt Accession P46109
Rabbit polyclonal, affinity-purified antibody is supplied in 100μl phosphate-buffered saline, 50% glycerol, 1 mg/ml BSA, and 0.05% sodium azide. Store at –20°C. Stable for 1 year.

The products are are safely shipped at ambient temperature for both domestic and international shipments. Each product is guaranteed to match the specifications as indicated on the corresponding technical data sheet. Please store at -20C upon arrival for long term storage.

This antibody was affinity purified using phospho-Crk II (Tyr-221) peptide (without carrier). The antibody detects a 40 kDa* protein corresponding to the molecular mass of Crk II on SDS-PAGE immunoblots of human K562 cells stimulated with pervanadate. This reactivity is not observed after akaline phosphatase treatment.

*All molecular weights (MW) are confirmed by comparison to Bio-Rad Rainbow Markers and to western blot mobilities of known proteins with similar MW.

This kit contains: