Phospho-AMPKα2 (Ser491) Antibody (Rabbit mAb) [J2M12]

Application: Reactivity: Human

Usage Information

Dilution
WB1:1000

Application
WB

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
62 kDa

Datasheet & SDS

Biological Description

Specificity
Phospho-AMPKα2 (Ser491) Antibody (Rabbit mAb) [J2M12] detects endogenous levels of total AMPKα2 protein only when it is phosphorylated at Ser491.

Clone
J2M12

Synonym(s)
AMPK, AMPK2, PRKAA2, 5'-AMP-activated protein kinase catalytic subunit alpha-2, AMPK subunit alpha-2, Acetyl-CoA carboxylase kinase, Hydroxymethylglutaryl-CoA reductase kinase, ACACA kinase, HMGCR kinase

Background
AMPKα2 belongs to the catalytic alpha subunit family of AMP-activated protein kinase, a heterotrimeric energy-sensing complex, and Ser491 sits within a serine/threonine-rich regulatory loop in the C-terminal domain of the alpha subunit, corresponding to the site known as Ser487 in AMPKα1. Multiple upstream kinases converge on this single residue to suppress AMPK activity through a mechanism distinct from the canonical Thr172 activation loop phosphorylation carried out by LKB1. Protein kinase D1 phosphorylates AMPKα2 directly at Ser491 in skeletal muscle cells, and this phosphorylation event inhibits AMPK activity and impairs downstream insulin signaling, establishing PKD1 as a direct negative regulator that links diacylglycerol-responsive signaling to AMPK suppression under conditions of lipid excess. In the hypothalamus, p70S6 kinase, acting downstream of the PI3K-Akt-mTOR axis, phosphorylates AMPKα2 specifically at Ser491 in response to leptin, and this phosphorylation reduces AMPK activity independently of any change in Thr172 phosphorylation, positioning Ser491 modification as a mechanistically separate regulatory node from the primary activation switch. This p70S6K-mediated phosphorylation at Ser491 is required for leptin's anorexigenic action on food intake, linking a single phosphorylation event on AMPKα2 directly to a physiological feeding behavior output. Notably, Akt itself phosphorylates the equivalent site on AMPKα1 at Ser487 in response to insulin or IGF-1, but AMPKα2 Ser491 is a comparatively poor substrate for Akt directly, meaning insulin-driven suppression of AMPKα2 activity proceeds through indirect or alternative kinases such as p70S6K rather than through direct Akt action at this site, a distinction that separates the regulatory logic of the two alpha isoforms despite their near-identical sequence position. Because phosphorylation at this regulatory loop blocks subsequent access of upstream kinases to the Thr172 activation site, Ser491 phosphorylation functions as an inhibitory switch that fine-tunes how readily AMPKα2 can be activated in a given metabolic state, making this phosphorylation event a marker of active negative-feedback signaling converging from insulin, leptin, and diacylglycerol-responsive pathways onto energy-sensing machinery, particularly relevant in skeletal muscle and hypothalamic tissue where insulin resistance and impaired appetite regulation are studied.

Background

AMPKα2 belongs to the catalytic alpha subunit family of AMP-activated protein kinase, a heterotrimeric energy-sensing complex, and Ser491 sits within a serine/threonine-rich regulatory loop in the C-terminal domain of the alpha subunit, corresponding to the site known as Ser487 in AMPKα1. Multiple upstream kinases converge on this single residue to suppress AMPK activity through a mechanism distinct from the canonical Thr172 activation loop phosphorylation carried out by LKB1. Protein kinase D1 phosphorylates AMPKα2 directly at Ser491 in skeletal muscle cells, and this phosphorylation event inhibits AMPK activity and impairs downstream insulin signaling, establishing PKD1 as a direct negative regulator that links diacylglycerol-responsive signaling to AMPK suppression under conditions of lipid excess. In the hypothalamus, p70S6 kinase, acting downstream of the PI3K-Akt-mTOR axis, phosphorylates AMPKα2 specifically at Ser491 in response to leptin, and this phosphorylation reduces AMPK activity independently of any change in Thr172 phosphorylation, positioning Ser491 modification as a mechanistically separate regulatory node from the primary activation switch. This p70S6K-mediated phosphorylation at Ser491 is required for leptin's anorexigenic action on food intake, linking a single phosphorylation event on AMPKα2 directly to a physiological feeding behavior output. Notably, Akt itself phosphorylates the equivalent site on AMPKα1 at Ser487 in response to insulin or IGF-1, but AMPKα2 Ser491 is a comparatively poor substrate for Akt directly, meaning insulin-driven suppression of AMPKα2 activity proceeds through indirect or alternative kinases such as p70S6K rather than through direct Akt action at this site, a distinction that separates the regulatory logic of the two alpha isoforms despite their near-identical sequence position. Because phosphorylation at this regulatory loop blocks subsequent access of upstream kinases to the Thr172 activation site, Ser491 phosphorylation functions as an inhibitory switch that fine-tunes how readily AMPKα2 can be activated in a given metabolic state, making this phosphorylation event a marker of active negative-feedback signaling converging from insulin, leptin, and diacylglycerol-responsive pathways onto energy-sensing machinery, particularly relevant in skeletal muscle and hypothalamic tissue where insulin resistance and impaired appetite regulation are studied.

References
https://pubmed.ncbi.nlm.nih.gov/22727014/ https://pubmed.ncbi.nlm.nih.gov/26797128/

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

Tech Support

Handling Instructions

Tel: +1-832-582-8158 Ext:3

If you have any other enquiries, please leave a message.

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%