SpecificityThis antibody was designed to recognise the activated form of Lck and was raised for that purpose against the linker that connects the SH2 domain and the tyrosine kinase domain of the kinase. This linker sits in the SH3 substrate binding site in the inactive kinase. The position of the linker is based on the crystal structure of inactive Src.
However, the antibody does not seem to distinguish the active and inactive forms of Lck. In IF, it recognises kinase dead Lck at the same concentration as constitutively active Lck.
In western blot, the antibody is highly specific for Lck versus other tyrosine kinases (see blot). Even, if the antibody was specific for active Lck in IF , it would be expected to recognise both active and inactive forms in Western blot. This is because the linker that the antibody recognises is present in both active and inactive Lck, it was just expected to be concealed in native form inactive Lck.
The application notes include recommended starting dilutions; optimal dilutions/concentrations should be determined by the end user.
1/1000. Detects a band of approximately 57 kDa (predicted molecular weight: 57 kDa).
1/200 - 1/500.
FunctionTyrosine kinase that plays an essential role for the selection and maturation of developing T-cell in the thymus and in mature T-cell function. Is constitutively associated with the cytoplasmic portions of the CD4 and CD8 surface receptors and plays a key role in T-cell antigen receptor(TCR)-linked signal transduction pathways. Association of the TCR with a peptide antigen-bound MHC complex facilitates the interaction of CD4 and CD8 with MHC class II and class I molecules, respectively, and thereby recruits the associated LCK to the vicinity of the TCR/CD3 complex. LCK then phosphorylates tyrosines residues within the immunoreceptor tyrosines-based activation motifs (ITAMs) in the cytoplasmic tails of the TCRgamma chains and CD3 subunits, initiating the TCR/CD3 signaling pathway. In addition, contributes to signaling by other receptor molecules. Associates directly with the cytoplasmic tail of CD2, and upon engagement of the CD2 molecule, LCK undergoes hyperphosphorylation and activation. Also plays a role in the IL2 receptor-linked signaling pathway that controls T-cell proliferative response. Binding of IL2 to its receptor results in increased activity of LCK. Is expressed at all stages of thymocyte development and is required for the regulation of maturation events that are governed by both pre-TCR and mature alpha beta TCR. Phosphorylates RUNX3.
Tissue specificityExpressed specifically in lymphoid cells.
Involvement in diseaseNote=A chromosomal aberration involving LCK is found in leukemias. Translocation t(1;7)(p34;q34) with TCRB.
Sequence similaritiesBelongs to the protein kinase superfamily. Tyr protein kinase family. SRC subfamily. Contains 1 protein kinase domain. Contains 1 SH2 domain. Contains 1 SH3 domain.
DomainThe SH2 domain mediates interaction with SQSTM1. Interaction is regulated by Ser-59 phosphorylation.
Post-translational modificationsPhosphorylated on Tyr-394, which increases enzymatic activity (By similarity). Phosphorylated on Tyr-505, which decreases activity.
Cellular localizationCytoplasm. Cell membrane. Present in lipid rafts in an unactive form.
FormThis protein is known to be similar in amino acid sequence to HCK (P08631), FYN (P06241), YES1 (P07947), SRC (P12931), and LYN (P07948). Therefore, cross-reactivity with these homologous proteins may be observed. We would be happy to provide immunogen alignment information upon request.
Lck p56 antibody
LCK proto-oncogene, Src family tyrosine kinase antibody
Leukocyte C-terminal Src kinase antibody
Lymphocyte cell specific protein tyrosine kinase antibody
Confocal immunofluorescence image of a COS cell transfected with a mouse Lck construct and stained with ab3885 at 1/200.
In untransfected cells, some nuclear staining is also visible as well as Lck staining.
Immunohistochemistry (Formalin/PFA-fixed paraffin-embedded sections) - Lck antibody (ab3885)This image is courtesy of an Abreview submitted by Antibody Solutions Ltd.
ab3885 staining Lck in human thymus tissue section by Immunohistochemistry (Formalin/PFA-fixed paraffin-embedded sections). Tissue underwent fixation in formaldehyde, heat mediated antigen retrieval and blocking was done for 15 minutes at 20°C (5 minutes of peroxidase block then 10 minutes of protein block) . The primary antibody was diluted, 1/2000 and incubated with sample for 45 minutes at 20°C. A HRP conjugated goat polyclonal to rabbit IgG was used, undiluted as secondary.
Rüder C et al. The tumor-associated antigen EBAG9 negatively regulates the cytolytic capacity of mouse CD8+ T cells. J Clin Invest119:2184-203 (2009).
IHC (PFA fixed)
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