MLK1 Antibody [M13M22] | Primary Antibodies

Application: Reactivity: Human, Mouse

Usage Information

Dilution
WB1:1000 IP1:50

Application
WB, IP

Reactivity
Human, Mouse

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
122 kDa

Datasheet & SDS

Biological Description

Specificity
MLK1 Antibody [M13M22] detects endogenous levels of total MLK1 protein.

Clone
M13M22

Synonym(s)
M3K9; MAP3K9; MEKK9; Mitogen-activated protein kinase kinase kinase 9; Mixed lineage kinase 1; mixed lineage kinase 1 (tyr and ser/thr specificity); MLK1; PRKE1

Background
MLK1 (MAP3K9; mixed‑lineage kinase 1) is a serine/threonine MAP kinase kinase kinase of the mixed‑lineage kinase subfamily that integrates small GTPase and stress inputs to selectively activate the MKK4/MKK7–JNK cascade and drive transcriptional and apoptotic responses to environmental change. The kinase contains an N‑terminal catalytic domain with sequence features of both tyrosine‑ and serine/threonine‑specific kinases, followed by two leucine/isoleucine zipper motifs that mediate homo‑ and hetero‑oligomerization, a C‑terminal basic region, and additional protein–protein interaction sequences, creating a modular scaffold suited for assembly of upstream regulators such as Rac1 and Cdc42 and downstream MAP2K substrates. Activation of MLK1 occurs through multisite autophosphorylation within the activation loop, where four serine/threonine residues act in concert: mutation of any single residue diminishes catalytic activity and JNK pathway activation, and phosphorylation on Thr312 is strictly required for full activation, with the T312A mutant retaining only basal activity and displaying electrophoretic mobility indistinguishable from kinase‑dead MLK1, indicating that Thr312 phosphorylation is the key step that licenses full activation loop phosphorylation and catalytic output. Once activated, MLK1 phosphorylates and activates the MAP2Ks MKK4 and MKK7, which in turn activate JNK isoforms that phosphorylate transcription factors including c‑Jun and GATA4, linking MLK1 activity to regulation of stress‑responsive gene expression, inflammatory mediators, and survival–apoptosis decisions. In neuronal contexts, MLK1 functions within the Rac1/Cdc42‑MKK4/7–JNK axis as an upstream activator of JNK‑dependent death signaling, contributing to mitochondrial apoptotic pathways characterized by cytochrome c release and executioner caspase activation; this places MLK1 as a mechanistic component of neuronal apoptosis and axonal degeneration pathways that are relevant to neurodegenerative and neurotoxic conditions. Expression of MLK1/MAP3K9 is documented in epithelial tumor cell lines of colonic, breast, and esophageal origin, implicating this kinase in oncogenic JNK signaling, stress adaptation, and potentially in responses to genotoxic or oxidative insults in cancer cells, while the broader mixed‑lineage kinase family is recognized as upstream regulators not only of JNK but also of p38 and ERK branches in specific cellular settings, suggesting that MLK1‑centered signaling nodes may influence proliferation, differentiation, and migration in addition to apoptosis.

Background

MLK1 (MAP3K9; mixed‑lineage kinase 1) is a serine/threonine MAP kinase kinase kinase of the mixed‑lineage kinase subfamily that integrates small GTPase and stress inputs to selectively activate the MKK4/MKK7–JNK cascade and drive transcriptional and apoptotic responses to environmental change. The kinase contains an N‑terminal catalytic domain with sequence features of both tyrosine‑ and serine/threonine‑specific kinases, followed by two leucine/isoleucine zipper motifs that mediate homo‑ and hetero‑oligomerization, a C‑terminal basic region, and additional protein–protein interaction sequences, creating a modular scaffold suited for assembly of upstream regulators such as Rac1 and Cdc42 and downstream MAP2K substrates. Activation of MLK1 occurs through multisite autophosphorylation within the activation loop, where four serine/threonine residues act in concert: mutation of any single residue diminishes catalytic activity and JNK pathway activation, and phosphorylation on Thr312 is strictly required for full activation, with the T312A mutant retaining only basal activity and displaying electrophoretic mobility indistinguishable from kinase‑dead MLK1, indicating that Thr312 phosphorylation is the key step that licenses full activation loop phosphorylation and catalytic output. Once activated, MLK1 phosphorylates and activates the MAP2Ks MKK4 and MKK7, which in turn activate JNK isoforms that phosphorylate transcription factors including c‑Jun and GATA4, linking MLK1 activity to regulation of stress‑responsive gene expression, inflammatory mediators, and survival–apoptosis decisions. In neuronal contexts, MLK1 functions within the Rac1/Cdc42‑MKK4/7–JNK axis as an upstream activator of JNK‑dependent death signaling, contributing to mitochondrial apoptotic pathways characterized by cytochrome c release and executioner caspase activation; this places MLK1 as a mechanistic component of neuronal apoptosis and axonal degeneration pathways that are relevant to neurodegenerative and neurotoxic conditions. Expression of MLK1/MAP3K9 is documented in epithelial tumor cell lines of colonic, breast, and esophageal origin, implicating this kinase in oncogenic JNK signaling, stress adaptation, and potentially in responses to genotoxic or oxidative insults in cancer cells, while the broader mixed‑lineage kinase family is recognized as upstream regulators not only of JNK but also of p38 and ERK branches in specific cellular settings, suggesting that MLK1‑centered signaling nodes may influence proliferation, differentiation, and migration in addition to apoptosis.

References
https://pubmed.ncbi.nlm.nih.gov/15610029/ https://pubmed.ncbi.nlm.nih.gov/17408454/

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%