Heterogeneous nuclear ribonucleoproteins A2/B1 is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
that in humans is encoded by the ''HNRNPA2B1''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
.
Structure
''HNRNPA2B1'' gene contains 12 exons, including a B1 protein specific 36-nucleotide mini-exon. The entire length of intron/exon organization of ''HNRNPA2B1'' is identical to that of the ''
HNRNPA1'' gene which indicates a common origin by gene duplication.
Function
This gene belongs to the A/B subfamily of ubiquitously expressed heterogeneous nuclear ribonucleoproteins (hnRNPs). The hnRNPs are RNA binding proteins and they complex with heterogeneous nuclear RNA (hnRNA). These proteins are associated with pre-mRNAs in the nucleus and appear to influence pre-mRNA processing and other aspects of mRNA metabolism and transport. While all of the hnRNPs are present in the nucleus, some seem to shuttle between the nucleus and the cytoplasm. The hnRNP proteins have distinct nucleic acid binding properties. The protein encoded by this gene has two repeats of quasi-RRM domains that bind to RNAs. This gene has been described to generate two alternatively spliced transcript variants which encode different isoforms.
HnRNPA2B1 is an autoantigen in autoimmune diseases such as
rheumatoid arthritis
Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and hands are involv ...
,
systemic lupus erythematosus
Lupus, technically known as systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Comm ...
and
mixed connective tissue disease
Mixed connective tissue disease, commonly abbreviated as MCTD, is an autoimmune disease characterized by the presence of elevated blood levels of a specific autoantibody, now called anti-U1 ribonucleoprotein (RNP) together with a mix of symptoms of ...
. When referred to as an
autoantigen
In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an "autoimmune disease". P ...
, hnRNPA2B1 is also known as
RA33.
The HNRNPA2 and HNRNPB1 proteins are involved in packaging nascent mRNA, in alternative splicing, and in cytoplasmic RNA trafficking, translation, and stabilization. HNRNPA2 and HNRNPB1 also appear to function in telomere maintenance, cell proliferation and differentiation, and glucose transport.
Function of HNRNPA2B1 gene can be effectively examined by siRNA knockdown based on an independent validation.
Interactions
HNRPA2B1 has been shown to
interact
Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization using innovative strategies to advocate for the legal and human rights of children with intersex traits. The organizati ...
with
casein kinase 2, alpha 1
Casein kinase II subunit alpha is an enzyme that in humans is encoded by the ''CSNK2A1'' gene.
Casein kinase II is a Serine/threonine-specific protein kinase, serine/threonine protein kinase that Phosphorylation, phosphorylates acidic proteins s ...
.
Role in diseases
The mutation p.D290V/302V in hnRNPA2B1 is implicated in dementia, myopathy, PDB, and ALS. Mutations in hnRNPA2B1 and hnRNPA1 cause of
amyotrophic lateral sclerosis
Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or Lou Gehrig's disease, is a neurodegenerative disease that results in the progressive loss of motor neurons that control voluntary muscles. ALS is the most comm ...
and
multisystem proteinopathy
Multisystem proteinopathy (MSP) is a dominantly inherited, pleiotropic, degenerative disorder of humans that can affect muscle, bone, and/or the central nervous system. MSP can manifest clinically as classical amyotrophic lateral sclerosis (ALS), ...
. hnRNPA2/B1 is found to activate cyclooxygenase-2 and promote tumor growth in human lung cancers.
[Xuan Yang, Wang Jingshu, Ban Liying, Lu Jian-Jun, Yi Canhui, Li Zhenglin, Yu Wendan, Li Mei, Xu Tingting, Yang Wenjing, Tang Zhipeng, Tang Ranran, Xiao Xiangsheng, Meng Songshu, Chen Yiming, Liu Quentin, Huang Wenlin, Guo Wei, Cui Xiaonan, Deng Wuguo, (2016), hnRNPA2/B1 activates cyclooxygenase-2 and promotes tumor growth in human lung cancers, Molecular Oncology, 10, doi: 10.1016/j.molonc.2015.11.010. Available from: http://onlinelibrary.wiley.com/doi/10.1016/j.molonc.2015.11.010/abstract;jsessionid=F7FAA0EE2ECB0751450320F2792BFD9E.f03t01]
References
Further reading
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{{PDB Gallery, geneid=3181