Background: GIT2 Protein Biology

GIT2 (G protein-coupled receptor kinase-interacting protein 2) is a multidomain scaffolding protein belonging to the GIT family, which also includes GIT1. GIT2 was originally identified through its interaction with G protein-coupled receptor kinases (GRKs) and has since been recognized as a central coordinator of intracellular signaling at focal adhesions, lamellipodia, and other cytoskeletal structures.

The protein contains several functional domains, including an ARF GAP (ADP-ribosylation factor GTPase-activating protein) domain at the N-terminus, ankyrin repeats, a Spa2-homology domain (SHD), coiled-coil regions, and a paxillin-binding subdomain (PBS) at the C-terminus. Through these domains, GIT2 engages partners such as PIX (PAK-interacting exchange factor), PAK (p21-activated kinase), paxillin, and focal adhesion kinase (FAK), forming multi-protein complexes that regulate cell migration, adhesion turnover, and actin dynamics.

GIT2 is ubiquitously expressed and plays roles in neuronal development, immune cell trafficking, and cancer cell invasion. Its ARF GAP activity toward ARF1 and ARF6 positions it as a regulatory node linking membrane trafficking to cytoskeletal remodeling.

Reagent Specifications and Storage Guidelines

Recombinant Human GIT2 Protein (rp367943) is manufactured as a recombinant protein for in vitro research use only. The following handling and storage recommendations apply to ensure optimal activity and stability over the product's shelf life.

• Storage Temperature: Upon receipt, store the protein at −80°C for long-term preservation. Avoid repeated freeze-thaw cycles, which can cause protein aggregation and loss of activity.
• Aliquoting: It is strongly recommended to prepare single-use aliquots immediately upon first thaw. This practice minimizes freeze-thaw damage and maintains protein integrity across experiments.
• Working Concentration: Determine empirically for each specific assay format. Refer to established literature for starting concentration ranges relevant to your application.
• Buffer Compatibility: Consult the product datasheet for the supplied formulation buffer. When exchanging buffers, use dialysis or desalting columns compatible with the protein's isoelectric point and stability range.
• Sterility and Endotoxin: For cell-based assays, verify endotoxin levels meet experimental requirements. Contact Aladdin Scientific technical support for lot-specific certificate of analysis data.

Note: Specific purity, concentration, and formulation details are provided on the product datasheet and certificate of analysis accompanying each lot. Review flag: confirm exact formulation and purity values from supplier documentation before publishing.

Recommended Experimental Applications

Recombinant Human GIT2 Protein is suited for a variety of biochemical and cell biology research applications. Researchers should validate the protein in their specific experimental system prior to use in critical experiments.

1. Protein–Protein Interaction Studies: GIT2 serves as a hub protein within the GIT/PIX/PAK/paxillin signaling complex. Recombinant GIT2 can be used in pull-down assays, co-immunoprecipitation validations, and surface plasmon resonance (SPR) or bio-layer interferometry (BLI) binding assays to characterize interaction partners and binding affinities.
2. ARF GAP Activity Assays: The ARF GAP domain of GIT2 catalyzes GTP hydrolysis on ARF family GTPases. Recombinant GIT2 can be employed in in vitro GAP activity assays using radiolabeled or FRET-based GTP hydrolysis methods to measure enzymatic kinetics or screen inhibitors.
3. Structural and Biophysical Studies: Purified recombinant GIT2 or its individual domains can be used in crystallography, cryo-EM sample preparation, small-angle X-ray scattering (SAXS), or NMR studies to elucidate structural features and conformational dynamics.
4. Antibody Validation and Western Blot Standards: Recombinant GIT2 protein serves as a positive control or standard in Western blotting, ELISA development, and immunoassay validation workflows.
5. Cell Signaling Reconstitution: In cell-free or reconstituted signaling systems, recombinant GIT2 can be incorporated to study its role in actin polymerization cascades downstream of integrins and growth factor receptors.

Quality Control and Troubleshooting

To ensure reproducible and reliable results with Recombinant Human GIT2 Protein, the following quality control practices and troubleshooting strategies are recommended:

Quality Control Checks

• SDS-PAGE / Western Blot Verification: Upon receipt, run a small aliquot on SDS-PAGE to confirm protein integrity and absence of major degradation bands. Verify molecular weight against the theoretical value for GIT2 (approximately 84 kDa for the full-length isoform; confirm exact value from the product datasheet).
• Protein Quantification: Use a BCA or Bradford assay to verify protein concentration against the supplied certificate of analysis value.
• Functional Activity Check: Where applicable, perform an ARF GAP activity assay with a validated ARF substrate to confirm biological activity of each new lot before committing to large-scale experiments.

Common Troubleshooting Issues

• Protein Aggregation: If aggregation is observed after thawing, centrifuge at 10,000–14,000 × g for 10 minutes at 4°C to remove aggregates before use. Avoid vortexing; mix gently by pipetting.
• Low Activity: Confirm that the protein has not undergone more than one freeze-thaw cycle. Check buffer compatibility and ensure assay conditions (pH, ionic strength, cofactors) match published optimal conditions for GIT2 activity.
• Non-specific Bands on Western Blot: Use a validated anti-GIT2 antibody and include appropriate negative controls. Recombinant GIT2 as a positive control can help distinguish specific from non-specific signals.

For lot-specific technical data, contact Aladdin Scientific technical support and reference SKU rp367943 and the lot number on the vial label.