CLCC1 Antibody

Definition and Characterization of CLCC1 Antibody

CLCC1 antibodies are immunological reagents specifically designed to detect the Chloride Channel CLIC-Like 1 protein in various research applications. These antibodies are available in multiple formats from different manufacturers, primarily as polyclonal antibodies raised in rabbits or monoclonal antibodies produced in mice, targeting various epitopes of the CLCC1 protein .

The target protein, CLCC1, is a 62 kDa transmembrane protein comprising 551 amino acids that functions as an anion-selective channel in the endoplasmic reticulum (ER) membrane . CLCC1 antibodies are critical for investigating this protein's role in maintaining ER ion homeostasis and its connection to neurodegenerative diseases.

Structure and Function

CLCC1 is a pore-forming component of an ER anion channel with three predicted transmembrane segments and an N-terminal signal peptide . The protein forms homomultimers in the ER membrane, as demonstrated by crosslinking experiments and co-immunoprecipitation assays . Functionally, CLCC1 operates as an anion-selective channel with Ca²⁺-dependent and voltage-independent gating properties .

The channel exhibits selectivity for small monovalent anions with a preference hierarchy of bromide > chloride > nitrate > fluoride . This selectivity profile is crucial for its physiological function in maintaining ion balance within the ER.

Physiological Significance

CLCC1 plays a critical role in ER function through several mechanisms:

1. It mediates chloride efflux to compensate for the loss of positive charges from the ER lumen during Ca²⁺ release

2. It maintains steady-state chloride ([Cl⁻]ᴇʀ) and potassium ([K⁺]ᴇʀ) concentrations in the ER

3. It regulates ER Ca²⁺ homeostasis, including internal Ca²⁺ release and steady-state [Ca²⁺]ᴇʀ

4. It contributes to ER morphology maintenance

5. It activates the unfolded protein response (UPR) to prevent accumulation of misfolded proteins

Disease Relevance

Research has linked CLCC1 dysfunction to neurodegenerative diseases, particularly amyotrophic lateral sclerosis (ALS). Studies have identified rare variants of CLCC1 in ALS patients, with these mutations impairing channel conductance . Disruption of ER ion homeostasis maintained by CLCC1 contributes to ALS-like pathologies through several mechanisms:

1. Impaired channel conductance increases steady-state [Cl⁻]ᴇʀ

2. Disrupted ER Ca²⁺ homeostasis leads to ER stress

3. Accumulated misfolded proteins in the ER lumen cause cellular dysfunction

4. Cell-autonomous motor neuron loss occurs following conditional knockout of Clcc1

Western Blotting

CLCC1 antibodies are extensively validated for western blotting applications, detecting the protein at approximately 50-62 kDa . Recommended dilutions typically range from 1:500 to 1:6000, depending on the specific antibody and sample type . Western blotting with CLCC1 antibodies has been successfully performed on various cell lines, including COLO320, U-251 MG, HepG2, A549, and HEK-293T .

Immunohistochemistry

For immunohistochemistry of paraffin-embedded tissues (IHC-P), CLCC1 antibodies have been validated at dilutions ranging from 1:50 to 1:500 . Successful staining has been reported in various human tissues including liver cancer and testis . Typical IHC protocols involve antigen retrieval using high-pressure treatment in citrate buffer (pH 6.0), followed by blocking with normal goat serum and overnight incubation with the primary antibody .

Immunoprecipitation

Several CLCC1 antibodies have demonstrated efficacy in immunoprecipitation experiments, typically used at dilutions of approximately 1:50 or 1-5 μL per mg of lysate . Immunoprecipitation has been successfully performed with CLCC1 antibodies on cell lysates from various sources, including HepG2 cells .

Immunocytochemistry/Immunofluorescence

For cellular localization studies, CLCC1 antibodies are used in immunofluorescence applications at dilutions of approximately 1:100 to 1:1000 . These applications have confirmed the predominantly ER localization of CLCC1, showing co-localization with ER markers such as CALNEXIN .

Knockout/Knockdown Validation

Some CLCC1 antibodies have been validated in knockout or knockdown experiments, providing confirmation of specificity . These validations are particularly important for antibodies used in functional studies of CLCC1 in disease models.

Working Dilutions

Optimal working dilutions vary by application and specific antibody:

CLCC1 in ALS Research

CLCC1 antibodies have become essential tools in investigating the connection between ER ion homeostasis disruption and amyotrophic lateral sclerosis. Studies have demonstrated that CLCC1 rare variants in ALS impair channel conductance, leading to disrupted ER ion homeostasis and characteristic ALS pathologies .

Research using CLCC1 antibodies has revealed that:

1. ALS-associated mutations increase steady-state [Cl⁻]ᴇʀ and impair ER Ca²⁺ homeostasis

2. Animals with ALS-associated CLCC1 mutations are sensitized to stress-induced protein misfolding

3. Conditional knockout of Clcc1 causes motor neuron loss, ER stress, and misfolded protein accumulation

4. 10% of K298A heterozygous mice (a model of CLCC1 mutation) developed ALS-like symptoms

Experimental Models

CLCC1 antibodies have been utilized in various experimental models to study neurodegenerative mechanisms:

1. Human 293FT cells with CLCC1 knockdown using shRNAs (H3 and H4)

2. Mice with ALS-associated CLCC1 mutations

3. Conditional knockout mouse models targeting Clcc1 in ChAT-positive motor neurons

4. Human tissue samples for comparative studies

Development of Specialized Antibodies

As research on CLCC1 progresses, there is potential for developing more specialized antibodies:

1. Phospho-specific antibodies targeting regulatory phosphorylation sites

2. Conformation-specific antibodies recognizing channel open/closed states

3. Mutation-specific antibodies for detecting ALS-associated CLCC1 variants

Therapeutic Applications

While current CLCC1 antibodies are primarily research tools, future developments might include:

1. Diagnostic antibodies for detecting CLCC1 abnormalities in patient samples

2. Therapeutic strategies targeting CLCC1 or its regulatory pathways

3. Biomarker development for monitoring disease progression