BLCAP

Last updated
BLCAP
Identifiers
Aliases BLCAP , BC10, bladder cancer associated protein, apoptosis inducing factor, BLCAP apoptosis inducing factor
External IDs OMIM: 613110 MGI: 1858907 HomoloGene: 38217 GeneCards: BLCAP
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_016916
NM_001355426

RefSeq (protein)

NP_058612
NP_001342355

Location (UCSC) Chr 20: 37.49 – 37.53 Mb Chr 2: 157.4 – 157.41 Mb
PubMed search [3] [4]
Wikidata
View/Edit Human View/Edit Mouse

Bladder cancer-associated protein is a protein that in humans is encoded by the BLCAP gene. [5] [6]

Contents

Function

BLCAP was identified using a differential display procedure with tumor biopsies obtained from a noninvasive and an invasive bladder transitional cell carcinoma. Although database searches revealed no homology to any human gene at the time of identification, mouse, rat and zebrafish orthologs have since been identified. The protein appears to be down-regulated during bladder cancer progression. [6]

The protein also known as BC10 is an 87-amino-acid-long protein, but its biological functions are largely unknown. However it is a widely believed that the protein is involved in tumour suppression by decreasing cell growth through initiating apoptosis. [7] It is widely expressed protein but expression is particularly high in brain and B lymphocytes. [8] Alternative promoters and alternative splicing allow the protein to exist as several different transcript variants. This number is further increased as the pre-mRNA of this protein is subject to several RNA editing events. [9]

Structure

The structure of the protein is predicted to be a globular protein with 2 transmembrane (TM) domains. [10]

RNA editing

The human BLCAP gene is composed of two exons which are separated by an intron. Exon 1 of the gene encodes a 5′ sequence of the 5′UTR while exon 2 includes the remaining sequence of the 5′UTR, the coding region and the 3′UTR. The coding sequence of the BLCAP gene is therefore intronless. [9]

Type

A to I RNA editing is catalyzed by a family of adenosine deaminases acting on RNA (ADARs) that specifically recognize adenosines within double-stranded regions of pre-mRNAs and deaminate them to inosine. Inosines are recognised as guanosine by the cells translational machinery. There are three members of the ADAR family ADARs 1-3 with ADAR 1 and ADAR 2 being the only enzymatically active members.ADAR3 is thought to have a regulatory role in the brain. ADAR1 and ADAR 2 are widely expressed in tissues while ADAR 3 is restricted to the brain. The double stranded regions of RNA are formed by base-pairing between residues in the close to region of the editing site with residues usually in a neighboring intron but can be an exonic sequence. The region that base pairs with the editing region is known as an Editing Complementary Sequence (ECS).

Location

The editing sites are all concentrated together between the last 150 nucleotides of intron 1 and the beginning of exon 2. There are 17 identified editing sites in total in the pre-mRNA of this protein. Of these, 11 are found within the intronic sequence (1-11), 3 are in the 5'UTR region (5a,5b,5c) while 3 are found within the coding sequence (Y/C site, Q/R site, K/R site). Some of these editing sites occur in the highly conserved amino terminal of the protein. [11]

The Y/C editing site is located at amino acid 2 of the final protein. The codon change introduces a tyrosine (UAU) to a (UGU) cysteine substitution. [12]

The Q/R site is a second coding region found at amino acid 5 of the final protein. Here the glutamine (Q_) is codon is converted to an arginine (R). [11]

The third K/R editing site within the coding sequence is found at amino acid position 15 of the final protein where a Lysine is converted to an Arginine. [11]

The ECS is predicted to be found in the intron with the double stranded structure formed containing all 17 of the editing sites. It is likely since all the editing sites fall within the duplex region that editing occurs in exonic and intronic sequences at the same time. There is a high level of conservation of the last 150 nucleotides of the intronic region and the start of exon 2. [11]

Regulation

The BLCAP protein is expressed in a wide range of tissues not just those associated with the nervous system. This indicates that editing may involve ADAR 1 enzyme. [9] However ADAR1 and ADAR2 have been demonstrated to cooperate to edit BLCAP transcript. The pre-mRNA of this protein is edited in many tissues( heart, bladder, lymphocytes, fibroblast, epithelial cells and brain) but the frequency of editing varies in different tissues. There is an overall decrease in BLCAP-editing level in Astrocytomas, Bladder cancer and Colorectal cancer when compared with the relevant normal tissues. HEK 293t cells transfected with either EGFP-ADAR1, EGFP-ADAR2 or untransfected HEK293 cells were used to determine which ADAR enzyme is involved in editing at specific sites in 5'UTR and coding region. The editing level at the Y/C site was 16% while in tumour cells was an average of 21% in brain. It has been shown that ADAR1 does not edit the sites in 5' UTR but ADAR2 edits 5b and 5c sites.Y/c is edited by both and edits the Q/R and K/R sites at higher levels than ADAR1. Low levels of editing are also detected in untransfected vectors. These results indicate that ADAR1 and ADAR2 can edited all sites with ADAR2 being more efficient at the majority of sites. [11]

Effects

Editing at the Q/R and K/R sites result in positively charge amino acids being placed in the conserved amino terminal of the protein. The three possible editing sites in the coding sequence can result in the translation of up to 8 different protein isoforms. [11] The possible changes to protein function caused by editing is unknown at the current time.

Related Research Articles

<span class="mw-page-title-main">Exon</span> A region of a transcribed gene present in the final functional mRNA molecule

An exon is any part of a gene that will form a part of the final mature RNA produced by that gene after introns have been removed by RNA splicing. The term exon refers to both the DNA sequence within a gene and to the corresponding sequence in RNA transcripts. In RNA splicing, introns are removed and exons are covalently joined to one another as part of generating the mature RNA. Just as the entire set of genes for a species constitutes the genome, the entire set of exons constitutes the exome.

<span class="mw-page-title-main">RNA splicing</span> Process in molecular biology

RNA splicing is a process in molecular biology where a newly-made precursor messenger RNA (pre-mRNA) transcript is transformed into a mature messenger RNA (mRNA). It works by removing all the introns and splicing back together exons. For nuclear-encoded genes, splicing occurs in the nucleus either during or immediately after transcription. For those eukaryotic genes that contain introns, splicing is usually needed to create an mRNA molecule that can be translated into protein. For many eukaryotic introns, splicing occurs in a series of reactions which are catalyzed by the spliceosome, a complex of small nuclear ribonucleoproteins (snRNPs). There exist self-splicing introns, that is, ribozymes that can catalyze their own excision from their parent RNA molecule. The process of transcription, splicing and translation is called gene expression, the central dogma of molecular biology.

<span class="mw-page-title-main">Alternative splicing</span> Process by which a gene can code for multiple proteins

Alternative splicing, or alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to code for multiple proteins. In this process, particular exons of a gene may be included within or excluded from the final, processed messenger RNA (mRNA) produced from that gene. This means the exons are joined in different combinations, leading to different (alternative) mRNA strands. Consequently, the proteins translated from alternatively spliced mRNAs will contain differences in their amino acid sequence and, often, in their biological functions.

<span class="mw-page-title-main">GRIA3</span> Mammalian protein found in Homo sapiens

Glutamate receptor 3 is a protein that in humans is encoded by the GRIA3 gene.

<span class="mw-page-title-main">FLNA</span> Protein-coding gene in the species Homo sapiens

Filamin A, alpha (FLNA) is a protein that in humans is encoded by the FLNA gene.

<span class="mw-page-title-main">ADAR</span> Mammalian protein found in Homo sapiens

The double-stranded RNA-specific adenosine deaminase enzyme family are encoded by the ADAR family genes. ADAR stands for adenosine deaminase acting on RNA. This article focuses on the ADAR proteins; This article details the evolutionary history, structure, function, mechanisms and importance of all proteins within this family.

<span class="mw-page-title-main">GRIA2</span> Mammalian protein found in Homo sapiens

Glutamate ionotropic receptor AMPA type subunit 2 is a protein that in humans is encoded by the GRIA2 gene and it is a subunit found in the AMPA receptors.

<span class="mw-page-title-main">IGFBP7</span>

Insulin-like growth factor-binding protein 7 is a protein that in humans is encoded by the IGFBP7 gene. The major function of the protein is the regulation of availability of insulin-like growth factors (IGFs) in tissue as well as in modulating IGF binding to its receptors. IGFBP7 binds to IGF with low affinity compared to IGFBPs 1-6. It also stimulates cell adhesion. The protein is implicated in some cancers.

<span class="mw-page-title-main">GRIK1</span> Protein-coding gene in the species Homo sapiens

Glutamate receptor, ionotropic, kainate 1, also known as GRIK1, is a protein that in humans is encoded by the GRIK1 gene.

<span class="mw-page-title-main">CYFIP2</span>

Cytoplasmic FMR1-interacting protein 2 is a protein that in humans is encoded by the CYFIP2 gene. Cytoplasmic FMR1 interacting protein is a 1253 amino acid long protein and is highly conserved sharing 99% sequence identity to the mouse protein. It is expressed mainly in brain tissues, white blood cells and the kidney.

<span class="mw-page-title-main">GRIA4</span>

Glutamate receptor 4 is a protein that in humans is encoded by the GRIA4 gene.

<span class="mw-page-title-main">GABRA3</span> Protein-coding gene in the species Homo sapiens

Gamma-aminobutyric acid receptor subunit alpha-3 is a protein that in humans is encoded by the GABRA3 gene.

<span class="mw-page-title-main">TMEM98</span>

Transmembrane protein 98 is a single-pass membrane protein that in humans is encoded by the TMEM98 gene. The function of this protein is currently unknown. TMEM98 is also known as UNQ536/PRO1079.

<span class="mw-page-title-main">ARL6IP4</span> Protein-coding gene in the species Homo sapiens

ADP-ribosylation-like factor 6 interacting protein 4 (ARL6IP4), also called SRp25 is the product of the ARL6IP4 gene located on chromosome 12q24. 31. Its function is unknown.

Within the science of molecular biology and cell biology, for human genetics, the GRIA2 gene is located on chromosome 4q32-q33. The gene product is the ionotropic AMPA glutamate receptor 2. The protein belongs to a family of ligand-activated glutamate receptors that are sensitive to alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA). Glutamate receptors function as the main excitatory neurotransmitter at many synapses in the central nervous system. L-glutamate, an excitatory neurotransmitter, binds to the Gria2 resulting in a conformational change. This leads to the opening of the channel converting the chemical signal to an electrical impulse. AMPA receptors (AMPAR) are composed of four subunits, designated as GluR1 (GRIA1), GluR2 (GRIA2), GluR3 (GRIA3), and GluR4(GRIA4) which combine to form tetramers. They are usually heterotrimeric but can be homodimeric. Each AMPAR has four sites to which an agonist can bind, one for each subunit.[5]

<span class="mw-page-title-main">C1QL1</span> Protein-coding gene in the species Homo sapiens

The complement component 1, q subcomponent-like 1 is encoded by a gene located at chromosome 17q21.31. It is a secreted protein and is 258 amino acids in length. The protein is widely expressed but its expression is highest in the brain and may also be involved in regulation of motor control. The pre-mRNA of this protein is subject to RNA editing.

Chimeric RNA, sometimes referred to as a fusion transcript, is composed of exons from two or more different genes that have the potential to encode novel proteins. These mRNAs are different from those produced by conventional splicing as they are produced by two or more gene loci.

<span class="mw-page-title-main">Circular RNA</span> Type of RNA found in cells

Circular RNA is a type of single-stranded RNA which, unlike linear RNA, forms a covalently closed continuous loop. In circular RNA, the 3' and 5' ends normally present in an RNA molecule have been joined together. This feature confers numerous properties to circular RNA, many of which have only recently been identified.

<span class="mw-page-title-main">DEPDC1B</span>

DEP Domain Containing Protein 1B also known as XTP1, XTP8, HBV XAg-Transactivated Protein 8, [formerly referred to as BRCC3] is a human protein encoded by a gene of similar name located on chromosome 5.

<span class="mw-page-title-main">TMEM171</span>

Transmembrane protein 171 (TMEM171) is a protein that in humans is encoded by the TMEM171 gene.

References

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Further reading