Phospho-c-Myc (Thr58) Antibody [L1K9]

Application: Reactivity: Human

Usage Information

Dilution
WB1:1000 IF1:250 FCM1:700

Application
WB, IF, FCM

Reactivity
Human

Source
Rabbit Monoclonal Antibody

Storage Buffer
PBS, pH 7.2+50% Glycerol+0.05% BSA+0.01% NaN3

Storage (from the date of receipt)
-20°C (avoid freeze-thaw cycles), 2 years

Predicted MW Observed MW
48 kDa 57 kDa
^*Why do the predicted and actual molecular weights differ? The following reasons may explain differences between the predicted and actual protein molecular weight.

Positive Control	HeLa cells; HeLa cells (Calyculin A, 200 nM; Okadaic Acid, 1 uM, 60 min)
Negative Control

Datasheet & SDS

Biological Description

Specificity
Phospho-c-Myc (Thr58) Antibody [L1K9] detects endogenous levels of total c-Myc protein only when it is phosphorylated at Thr58.

Clone
L1K9

Synonym(s)
BHLHE39; MYC; Myc proto-oncogene protein; Class E basic helix-loop-helix protein 39; Proto-oncogene c-Myc; Transcription factor p64; bHLHe39

Background
Phospho-c-Myc Thr58 refers to the threonine-58 phosphorylated form of c-Myc, which is a proto-oncogenic basic helix-loop-helix leucine zipper transcription factor at the core of the Myc/Max/Mad network, regulating a significant portion of the genome involved in cell proliferation, metabolism, and apoptosis. c-Myc comprises an N-terminal transactivation domain containing Myc box I and II with Thr58 and Ser62 residues, a central HLH-LZ motif for heterodimerization with Max and binding to E-box DNA sequences, and a C-terminal region with degradation signals. Phosphorylation at Thr58, which is primed by prior phosphorylation of Ser62 by ERK or CDKs, is mediated by GSK-3 beta and creates a site for dephosphorylation at Ser62 by PP2A. This event recruits the SCF-Fbw7 E3 ligase, leading to K48-linked ubiquitination at lysines such as Lys57 and Lys161 and subsequent proteasomal degradation of c-Myc, resulting in a short protein half-life of about 20 to 30 minutes. The presence of phospho-Thr58 destabilizes c-Myc, limits its transcriptional activation of growth-related genes like nucleolin, CDK4, and hTERT, and influences its subnuclear localization to promyelocytic leukemia bodies with GSK-3, ultimately reducing its oncogenic potential. This phosphorylation enforces rapid turnover of Myc, maintaining homeostatic control during mitogen signaling. phospho-Thr58 helps balance Ras and ERK-driven proliferation with protein degradation checkpoints during the G1 to S phase transition and spindle assembly. Mutations at Thr58, such as T58A, prevent phosphorylation, stabilize c-Myc, enhance cellular transformation, and result in genomic instability due to dysregulation of the spindle assembly checkpoint and upregulation of Aurora B. Loss or absence of phospho-Thr58 is frequently observed in Burkitt lymphoma, where it represents a common mutational hotspot, as well as in other MYC-driven cancers including breast and prostate cancer, and is associated with poor prognosis due to uncontrolled Myc activity.

Background

Phospho-c-Myc Thr58 refers to the threonine-58 phosphorylated form of c-Myc, which is a proto-oncogenic basic helix-loop-helix leucine zipper transcription factor at the core of the Myc/Max/Mad network, regulating a significant portion of the genome involved in cell proliferation, metabolism, and apoptosis. c-Myc comprises an N-terminal transactivation domain containing Myc box I and II with Thr58 and Ser62 residues, a central HLH-LZ motif for heterodimerization with Max and binding to E-box DNA sequences, and a C-terminal region with degradation signals. Phosphorylation at Thr58, which is primed by prior phosphorylation of Ser62 by ERK or CDKs, is mediated by GSK-3 beta and creates a site for dephosphorylation at Ser62 by PP2A. This event recruits the SCF-Fbw7 E3 ligase, leading to K48-linked ubiquitination at lysines such as Lys57 and Lys161 and subsequent proteasomal degradation of c-Myc, resulting in a short protein half-life of about 20 to 30 minutes. The presence of phospho-Thr58 destabilizes c-Myc, limits its transcriptional activation of growth-related genes like nucleolin, CDK4, and hTERT, and influences its subnuclear localization to promyelocytic leukemia bodies with GSK-3, ultimately reducing its oncogenic potential. This phosphorylation enforces rapid turnover of Myc, maintaining homeostatic control during mitogen signaling. phospho-Thr58 helps balance Ras and ERK-driven proliferation with protein degradation checkpoints during the G1 to S phase transition and spindle assembly. Mutations at Thr58, such as T58A, prevent phosphorylation, stabilize c-Myc, enhance cellular transformation, and result in genomic instability due to dysregulation of the spindle assembly checkpoint and upregulation of Aurora B. Loss or absence of phospho-Thr58 is frequently observed in Burkitt lymphoma, where it represents a common mutational hotspot, as well as in other MYC-driven cancers including breast and prostate cancer, and is associated with poor prognosis due to uncontrolled Myc activity.

References
https://pubmed.ncbi.nlm.nih.gov/14563837/ https://pubmed.ncbi.nlm.nih.gov/15103331/

Reference Table for Selecting PVDF Membrane Pore Size Specifications

Protein Size (kDa)	PVDF Transfer Membrane Pore Size (μm)
< 10	0.22
10-20	0.22
20-30	0.45
30-45	0.45
45-70	0.45
80-100	0.45
100-140	0.45
> 140	0.45

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Protein Size (kDa)	Separating Gel Percentage
4-40	20%
12-45	15%
10-70	12.5%
15-100	10%
25-100	8%
60-210	5%