A-kinase anchor protein 4 is a scaffold protein that in humans is encoded by the ''AKAP4''
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 ...
.
It involves in the intracellular signalling of protein kinase -A. AKAP4 is called as cancer /testis antigen (CTA), it belongs to a class of
tumour
A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...
linked antigens categories by high expression in germ cells and cancer than normal tissues. AKAP4 is not normally expressed in
mRNA
In molecular biology, messenger ribonucleic acid (mRNA) is a single-stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of Protein biosynthesis, synthesizing a protein.
mRNA is ...
and protein level in MM cell line.
Function
The A-kinase anchor proteins (AKAPs) are a group of structurally diverse proteins, which have the common function of binding to the regulatory subunit of
protein kinase A
In cell biology, protein kinase A (PKA) is a family of enzymes whose activity is dependent on cellular levels of cyclic AMP (cAMP). PKA is also known as cAMP-dependent protein kinase (). PKA has several functions in the cell, including regulatio ...
(PKA) and confining the holoenzyme to discrete locations within the cell. This gene encodes a member of the AKAP family. The encoded protein is localized to the sperm
flagellum
A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates.
A microorganism may have f ...
and may be involved in the regulation of sperm motility. Alternative splicing of this gene results in two transcript variants encoding different isoforms.
AKAP 4 protein belongs to the family of
scaffold protein
In biology, scaffold proteins are crucial regulators of many key signalling pathways. Although scaffolds are not strictly defined in function, they are known to interact and/or bind with multiple members of a signalling pathway, tethering them in ...
s and is involved in controlled mechanism of flagellar function.
In mice, AKAP4 is required for sperm development and male mice that lack AKAP4 are infertiel The fibrous sheath was not formed, flagellum become short and often some proteins associated with the fibrous sheath in this case they were very few or absent. Surprisingly, another component of flagellum was developed as normal. In the conclusion, they state that AKAP4 plays a pivotal role in the fibrous sheath and effect on the motility of sperm, in the absence of AKAP4 these activities affected due to a failure of signal transduction and glycolytic enzymes because they were not able to attach with the fibrous sheath.
Clinical significance
AKAP4 is a potential biomarker for early diagnosis and immunotherapy of colon cancer. AKAP4 may be implicated as a biomarker and immunotherapeutic target for cervical cancer. AKAP4 is also a circulating biomarker for non-small cell lung cancer. To detect the early stage breast cancer and diagnosis, AKAP4 is used as serum. Investigation was undertaken about AKAP4 with various clinical parameters which could be use as early detector biomarker to treat cancer by developing a tissue or serum.
AKAP4 is associated with diseases such as multiple myeloma, lung cancer, breast cancer and prostate cancer.
AKAP4 is over expressed in
multiple myeloma
Multiple myeloma (MM), also known as plasma cell myeloma and simply myeloma, is a cancer of plasma cells, a type of white blood cell that normally produces antibodies. Often, no symptoms are noticed initially. As it progresses, bone pain, an ...
(MM)
Interactions
AKAP4 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:
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AKAP3,
[ and
* ]PRKAR1A
cAMP-dependent protein kinase type I-alpha regulatory subunit is an enzyme that in humans is encoded by the ''PRKAR1A'' gene.
Function
cAMP is a signaling molecule important for a variety of cellular functions. cAMP exerts its effects by activ ...
.
References
Further reading
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External links
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A-kinase-anchoring proteins
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