GABARAP Antibody (Rabbit mAb) [P12P16]

Application: Reactivity: Human

Usage Information

Dilution
WB1:1000 IHC1:100 - 1:250

Application
WB, IHC

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
14 kDa 17 kDa
^*Why do the predicted and actual molecular weights differ? The following reasons may explain differences between the predicted and actual protein molecular weight. Post-translational modifications(e.g., phosphorylation, glycosylation); Splice variants and isoforms; Relative charge; Multimerization.

Positive Control	Human fetal brain tissue; Human heart tissue; SH-SY5Y cells; Flag-GABARAP
Negative Control

Datasheet & SDS

Biological Description

Specificity
GABARAP Antibody (Rabbit mAb) [P12P16] detects endogenous levels of total GABARAP protein.

Clone
P12P16

Synonym(s)
FLC3B, HT004, GABARAP, Gamma-aminobutyric acid receptor-associated protein, GABA(A) receptor-associated protein, MM46

Background
GABARAP, gamma-aminobutyric acid receptor-associated protein, belongs to the ATG8 family of ubiquitin-like modifiers, sitting within the GABARAP/GATE-16 subfamily that is functionally distinct from the LC3 subfamily also encoded by ATG8 orthologs. While LC3 proteins drive elongation of the growing phagophore membrane during autophagosome formation, GABARAP subfamily members act at a later stage, supporting autophagosome maturation rather than initial membrane expansion. GABARAP performs this maturation function through direct, LC3-interacting-region-dependent binding to receptor proteins displayed on cargo destined for degradation, and this receptor-based recognition mechanism extends beyond bulk cytoplasmic autophagy into organelle-selective clearance. In reticulophagy, the selective autophagic turnover of the endoplasmic reticulum, GABARAP engages the ER-resident receptor TEX264, a single-pass transmembrane protein whose C-terminal cytosolic region carries a single LC3-interacting motif; the ATG8-containing isolation membrane cradles a tubular segment of TEX264-positive ER at three-way junctions, forming a synapse of two juxtaposed membranes held together by trans interaction between TEX264 and ATG8-family proteins including GABARAP, and expansion of the isolation membrane extends this ER capture in a zipper-like process until membrane fission closes the autophagosome around the captured ER fragment. Beyond its role in membrane trafficking, GABARAP functions as a membrane-localized signaling scaffold independent of autophagy: it recruits a CUL3 RING ubiquitin ligase complex built from the substrate adaptors KBTBD6 and KBTBD7, which engage GABARAP preferentially over other ATG8 family members through dedicated ATG8-interacting motifs, and this GABARAP-anchored complex ubiquitylates TIAM1, a RAC1-specific guanine nucleotide exchange factor, targeting it for proteasomal degradation. Binding to GABARAP is required for this ubiquitylation event to proceed, meaning GABARAP does not merely tether the ligase complex to membranes but is mechanistically necessary for TIAM1 turnover itself; depleting KBTBD6 and KBTBD7 increases TIAM1 abundance, elevates RAC1 activity, alters actin cytoskeletal morphology, reduces focal adhesions, and enhances invasive cell behavior, directly linking GABARAP-scaffolded ubiquitin ligase activity to spatial restriction of RAC1-driven cytoskeletal signaling and cell motility. Through these two mechanistically distinct roles, membrane-remodeling receptor engagement during ER-phagy and ubiquitin ligase scaffolding during RAC1 pathway regulation, GABARAP functions as a dual-purpose ATG8 protein positioned at the interface of organelle quality control and localized signal transduction, making it a relevant target for researchers studying selective autophagy substrate specificity as well as spatially restricted small GTPase signaling in cell migration and proliferation.

Background

GABARAP, gamma-aminobutyric acid receptor-associated protein, belongs to the ATG8 family of ubiquitin-like modifiers, sitting within the GABARAP/GATE-16 subfamily that is functionally distinct from the LC3 subfamily also encoded by ATG8 orthologs. While LC3 proteins drive elongation of the growing phagophore membrane during autophagosome formation, GABARAP subfamily members act at a later stage, supporting autophagosome maturation rather than initial membrane expansion. GABARAP performs this maturation function through direct, LC3-interacting-region-dependent binding to receptor proteins displayed on cargo destined for degradation, and this receptor-based recognition mechanism extends beyond bulk cytoplasmic autophagy into organelle-selective clearance. In reticulophagy, the selective autophagic turnover of the endoplasmic reticulum, GABARAP engages the ER-resident receptor TEX264, a single-pass transmembrane protein whose C-terminal cytosolic region carries a single LC3-interacting motif; the ATG8-containing isolation membrane cradles a tubular segment of TEX264-positive ER at three-way junctions, forming a synapse of two juxtaposed membranes held together by trans interaction between TEX264 and ATG8-family proteins including GABARAP, and expansion of the isolation membrane extends this ER capture in a zipper-like process until membrane fission closes the autophagosome around the captured ER fragment. Beyond its role in membrane trafficking, GABARAP functions as a membrane-localized signaling scaffold independent of autophagy: it recruits a CUL3 RING ubiquitin ligase complex built from the substrate adaptors KBTBD6 and KBTBD7, which engage GABARAP preferentially over other ATG8 family members through dedicated ATG8-interacting motifs, and this GABARAP-anchored complex ubiquitylates TIAM1, a RAC1-specific guanine nucleotide exchange factor, targeting it for proteasomal degradation. Binding to GABARAP is required for this ubiquitylation event to proceed, meaning GABARAP does not merely tether the ligase complex to membranes but is mechanistically necessary for TIAM1 turnover itself; depleting KBTBD6 and KBTBD7 increases TIAM1 abundance, elevates RAC1 activity, alters actin cytoskeletal morphology, reduces focal adhesions, and enhances invasive cell behavior, directly linking GABARAP-scaffolded ubiquitin ligase activity to spatial restriction of RAC1-driven cytoskeletal signaling and cell motility. Through these two mechanistically distinct roles, membrane-remodeling receptor engagement during ER-phagy and ubiquitin ligase scaffolding during RAC1 pathway regulation, GABARAP functions as a dual-purpose ATG8 protein positioned at the interface of organelle quality control and localized signal transduction, making it a relevant target for researchers studying selective autophagy substrate specificity as well as spatially restricted small GTPase signaling in cell migration and proliferation.

References
https://pubmed.ncbi.nlm.nih.gov/31006538/ https://pubmed.ncbi.nlm.nih.gov/25684205/

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%