Alphaklotho is a single-pass transmembrane and soluble protein factor extensively studied in preclinical models for its role in phosphate homeostasis, oxidative stress mitigation, and cellular senescence regulation. It functions primarily as an obligate co-receptor for fibroblast growth factor 23 (FGF23), modulating downstream signaling cascades implicated in aging research and tissue homeostasis. PX1 Research supplies high-purity, laboratory-grade alphaklotho specifically designed for rigorous in vitro and animal model research applications.
Alphaklotho is a single-pass transmembrane and soluble protein factor extensively studied in preclinical models for its role in phosphate homeostasis, oxidative stress mitigation, and cellular senescence regulation. It functions primarily as an obligate co-receptor for fibroblast growth factor 23 (FGF23), modulating downstream signaling cascades implicated in aging research and tissue homeostasis. PX1 Research supplies high-purity, laboratory-grade alphaklotho specifically designed for rigorous in vitro and animal model research applications.
In biochemical literature, alphaklotho (often designated as α-Klotho or Klotho) exists in two primary functional forms: a full-length single-pass transmembrane protein and a truncated, soluble circulating variant. The full-length transmembrane protein consists of a large extracellular domain, a single transmembrane region, and a short intracellular carboxyl-terminal tail. The extracellular domain comprises two internal repeats, termed KL1 and KL2, which display sequence homology to family 1 β-glucosidases.
Soluble alphaklotho is generated via two distinct mechanisms: direct gene splicing leading to a secreted transcript, or proteolytic cleavage of the extracellular domain of the transmembrane isoform by membrane-anchored metalloproteinases such as ADAM10 and ADAM17. This soluble form enters systemic circulation and cerebrospinal fluid, acting as a humoral factor with enzymatic and receptor-modulating activities independent of membrane localization. Investigators working with alphaklotho signaling pathways frequently evaluate both full-length recombinant proteins and specific domain fragments across various all-peptides library screens.
The canonical endocrine activity of transmembrane alphaklotho centers on its role as an essential co-receptor for Fibroblast Growth Factor 23 (FGF23). FGF23 regulates systemic phosphate and vitamin D homeostasis, but its affinity for canonical FGF receptors (FGFR1c, FGFR3c, FGFR4) in isolation is remarkably low. Transmembrane alphaklotho physical complexation with FGFR increases receptor binding affinity for FGF23 by several orders of magnitude, forming a functional binary or ternary signaling complex.
In renal proximal tubule research models, the FGF23–alphaklotho–FGFR complex initiates downstream intracellular phosphorylation cascades, specifically activating the extracellular signal-regulated kinase (ERK1/2) and p38 MAPK pathways. This signaling cascade results in the down-regulation of sodium-phosphate cotransporters (NaPi-2a and NaPi-2c) on the apical membrane, suppressing renal phosphate reabsorption. Simultaneously, this complex inhibits 1α-hydroxylase expression, reducing active 1,25-dihydroxyvitamin D synthesis. Researchers utilizing the PX1 research hub evaluate these mechanisms to elucidate mineral axis feedback loops.
Beyond mineral homeostasis, alphaklotho has gained significant attention in biogerontology models due to its observed suppression in senescent cell populations and animal models of accelerated aging. In vitro assays demonstrate that soluble alphaklotho functions as an endogenous inhibitor of Wnt signaling pathways. Overactive Wnt signaling is associated with stem cell depletion and cellular senescence; by binding to Wnt ligands, soluble alphaklotho mitigates downstream β-catenin translocation.
Furthermore, preclinical animal models exhibit altered insulin and insulin-like growth factor-1 (IGF-1) receptor signaling in the presence of elevated circulating alphaklotho. Soluble alphaklotho induces moderate resistance to insulin and IGF-1 signaling at the receptor level, triggering nuclear translocation of FOXO transcription factors. This mechanism leads to up-regulated expression of endogenous antioxidant enzymes, such as superoxide dismutase (SOD) and catalase, mitigating intracellular reactive oxygen species (ROS) accumulation. Detailed examinations of these pathways are regularly cataloged in longevity and cellular senescence research frameworks.
Renal tissue represents the primary physiological site of endogenous alphaklotho expression. In rodent models of acute kidney injury (AKI) and chronic kidney disease (CKD), renal expression of alphaklotho drops precipitously. Research demonstrates that recombinant alphaklotho administration in rodent injury models suppresses renal fibrosis by antagonizing transforming growth factor-beta 1 (TGF-β1) signaling and inhibiting epithelial-to-mesenchymal transition (EMT).
In cardiovascular preclinical paradigms, alphaklotho demonstrates protective signaling effects within endothelial cells and vascular smooth muscle tissue. In vitro studies using human umbilical vein endothelial cells (HUVECs) show that soluble alphaklotho stimulates nitric oxide production via endothelial nitric oxide synthase (eNOS) phosphorylation. Furthermore, in rodent models of arterial stiffness, alphaklotho attenuates vascular calcification by regulating inorganic phosphate uptake and maintaining Na+/K+-ATPase membrane transport stability.
To ensure precise, reproducible experimental outcomes, research-grade alphaklotho must meet strict biochemical criteria. Recombinant proteins and long-chain peptide constructs are highly susceptible to conformational heterogeneity, aggregation, and bacterial endotoxin contamination, all of which can severely confound cell culture assays and animal signaling data.
PX1 Research enforces stringent quality assurance criteria across all production lots, operating within ISO 17025 accredited laboratory environments and GMP-compliant facilities. Every batch undergoes reverse-phase high-performance liquid chromatography (RP-HPLC) to confirm high purity (typically ≥95–98%), alongside matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) to verify exact molecular weight and amino acid fidelity. For institutional clients establishing wholesale and bulk lab accounts, each lot is accompanied by a comprehensive Certificate of Analysis (COA) detailing HPLC chromatograms, mass spectra, and strict endotoxin quantification (<0.01 EU/μg via LAL assay).
Proper handling of lyophylized alphaklotho is vital to maintain protein tertiary structure and biological activity. Upon receiving the lyophilized vial, laboratories should perform a brief low-speed centrifugation (10,000 x g for 30–60 seconds) to consolidate the powder at the bottom of the vessel prior to opening the stopper.
Reconstitution should be executed using sterile, endo-free water or phosphate-buffered saline (PBS, pH 7.4) to achieve a primary stock concentration between 0.1 mg/mL and 1.0 mg/mL. For low-concentration working solutions, adding a carrier protein such as 0.1% endotoxin-free Bovine Serum Albumin (BSA) or Human Serum Albumin (HSA) is highly recommended to prevent non-specific adsorption to plastic microcentrifuge tubes or pipet tips. Reconstitution and aliquoting protocols are further detailed on individual product pages like recombinant alphaklotho.
When designing preclinical longevity and senescence protocols, researchers frequently compare alphaklotho with other benchmark research compounds targeting cell cycle arrest, telomerase function, or mitochondrial stability. While alphaklotho operates principally through systemic endocrine co-receptor signaling, Wnt inhibition, and IGF-1 axis modulation, alternative compounds interact with distinct cell-intrinsic targets.
For instance, FOXO4-DRI is a targeted senolytic peptide engineered to disrupt the intracellular p53-FOXO4 interaction, selective inducing apoptosis in senescent cell lines. In contrast, Epithalon acts primarily as a synthetic tetrapeptide studied for its capacity to up-regulate telomerase activity and influence pineal chromatin structure. Meanwhile, SS-31 is a mitochondria-targeted antioxidant peptide that selectively binds to cardiolipin in the inner mitochondrial membrane to optimize electron transport chain efficiency. Selecting between or combining these compounds depends on whether the laboratory aims to target systemic hormonal co-receptor pathways (alphaklotho), selective senolysis (FOXO4-DRI), telomere dynamics (Epithalon), or bioenergetic membrane integrity (SS-31).
Lyophilized alphaklotho should be stored in a manual-defrost freezer at -20°C to -80°C upon receipt, where it remains stable for up to 24 months. Exposure to repeated freeze-thaw cycles must be rigorously avoided, as temperature fluctuations cause irreversible protein denaturation, aggregation, and loss of receptor-binding affinity.
Once reconstituted into aqueous solution, stock solutions may be kept at 2°C to 8°C for short-term assays (not exceeding 2 to 7 days). For long-term functional storage, stock solutions should be immediately divided into single-use micro-aliquots using low-binding polypropylene tubes and stored at -80°C. Thawed aliquots should be used immediately and should never be returned to the freezer.
Sourcing high-integrity research compounds requires an uncompromised supply chain. PX1 Research synthesizes and manufactures compounds in domestic USA facilities, enforcing rigorous oversight from raw amino acid acquisition to final vial packaging. This domestic framework guarantees lot traceability and eliminates the purity variance commonly associated with unverified overseas distributors.
To safeguard reagent stability during transit, all orders ship directly from centralized fulfillment hubs located in California and Arizona. PX1 Research provides same-day dispatch for orders finalized Monday through Friday before cut-off times, delivering rapid transit across North America. Laboratories can browse related specialized compounds across our mitochondrial peptides library for complementary experimental assays.
What is alphaklotho in research peptide studies?
Alphaklotho is a single-pass transmembrane and circulating protein studied in preclinical models for its role as an essential co-receptor for FGF23, regulating phosphate homeostasis, Wnt signaling, and cellular senescence pathways.
How does alphaklotho function as an FGF23 co-receptor?
Transmembrane alphaklotho forms a high-affinity complex with canonical Fibroblast Growth Factor Receptors (FGFRs), enabling FGF23 binding and downstream ERK1/2 and p38 MAPK signaling in renal and cardiovascular tissues.
What is the difference between transmembrane and soluble alphaklotho?
Transmembrane alphaklotho is localized to the cell membrane and functions primarily in local FGF23 co-receptor signaling. Soluble alphaklotho is generated via alternative splicing or ADAM10/17 cleavage, circulating systemically to act as an endocrine regulator of Wnt, insulin/IGF-1, and ROS pathways.
What purity levels are required for alphaklotho in vitro assays?
Cell culture and biochemical assays typically require a minimum purity of 95% to 98%, verified by RP-HPLC and mass spectrometry, to prevent unspecific cellular stress or artifactual assay results.
How should recombinant alphaklotho be reconstituted in the lab?
Reconstitution should be performed using sterile, endotoxin-free water or PBS (pH 7.4) to a concentration of 0.1–1.0 mg/mL, ideally adding 0.1% BSA or HSA to prevent protein binding to container walls.
How does alphaklotho compare to FOXO4-DRI in senescence research?
Alphaklotho acts as a systemic co-receptor and signal modulator that mitigates cellular senescence cascades, whereas FOXO4-DRI is a cell-permeable peptide that selectively triggers apoptosis in established senescent cells by disrupting p53 binding.
What are the recommended storage temperatures for lyophilized alphaklotho?
Lyophilized powder should be stored long-term at -20°C to -80°C in a manual-defrost freezer protected from moisture and direct light.
What analytical methods verify alphaklotho lot purity and endotoxin levels?
Every lot is verified using Reverse-Phase HPLC for purity percentage, MALDI-TOF or ESI Mass Spectrometry for molecular weight identification, and LAL assays to confirm endotoxin levels (<0.01 EU/μg).
Can alphaklotho be purchased in bulk for institutional lab accounts?
Yes, PX1 Research provides institutional tier purchasing and custom bulk orders complete with lot-specific COAs for verified laboratory accounts.
How does PX1 Research ship alphaklotho to maintain stability?
Orders are dispatched same-day (Monday through Friday) from CA and AZ fulfillment centers using temperature-controlled, expedited shipping protocols to prevent thermal degradation during transit.
All products are sold strictly for laboratory and research use only. Not for human or veterinary use, diagnosis, treatment or consumption. Statements have not been evaluated by the FDA.