Transmembrane protein 229b 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 TMEM229b
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 ...
.
Nomenclature
The TMEM229B gene is also known as C14orf83, FLJ33387, Q8NBD8, Hs.509707, Hs.712258, IPR010540, and CN083_HUMAN.
Gene
The TMEM229B gene is located on the
sense strand
In genetics, a sense strand, or coding strand, is the segment within double-stranded DNA that carries the translatable code in the 5′ to 3′ direction, and which is complementary to the antisense strand of DNA, or template strand, which doe ...
(-) of chromosome 14 at location 14q24.1 and spans the chromosomal locus 67,936,983—67,982,021.
Covering a total of 45,038
base pairs
A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA ...
(bp) along the chromosome, the TMEM229B gene has a total of 3 exons in its primary unspliced transcript
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 ...
of 4,068 bp. There are a total of 7 transcript variants for TMEM229B ranging in mRNA size from 519 bp to 5008 bp.
The TMEM229B gene is flanked by phosphatidylinositol glycan anchor class H (
PIGH
Phosphatidylinositol N-acetylglucosaminyltransferase subunit H is an enzyme that in humans is encoded by the ''PIGH'' gene. The PIGH gene is located on the reverse strand of chromosome 14 in humans, and is neighbored by TMEM229B.
This gene encodes ...
), a protein associated with the endoplasmic reticulum specifically GPI-anchor biosynthesis, and PLEK2 on its left.
See Figure 1.0. The gene is highly conserved in vertebrates, including portions of the approximately 3,000 base pairs of
3'UTR.
Tissue distribution
Expressed sequence tag In genetics, an expressed sequence tag (EST) is a short sub-sequence of a cDNA sequence. ESTs may be used to identify gene transcripts, and were instrumental in gene discovery and in gene-sequence determination. The identification of ESTs has proce ...
mapping of TMEM229B gene expression indicates that it is ubiquitously expressed throughout the body. TMEM229B is more heavily expressed in the
parathyroid
Parathyroid glands are small endocrine glands in the neck of humans and other tetrapods. Humans usually have four parathyroid glands, located on the back of the thyroid gland in variable locations. The parathyroid gland produces and secretes par ...
, skin, and
thyroid
The thyroid, or thyroid gland, is an endocrine gland in vertebrates. In humans it is in the neck and consists of two connected lobes. The lower two thirds of the lobes are connected by a thin band of tissue called the thyroid isthmus. The thy ...
tissues, and moderately expressed in bone marrow, trachea, spleen, eye, brain, pancreas, mammary gland, intestine, liver, thymus, lymph node, ovarian, muscle, lung, blood, and kidney tissues.
Protein
The translated TMEM229B protein is a total of 167 amino acids long, with a predicted
molecular weight
A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioch ...
of 19,531
Daltons. The TMEM229B protein contains a domain of unknown function, part of the domain family DUF1113, spanning from
amino acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...
s 87 to 135.
Based on predicted structure TMEM229b is highly resemblant of a
connexin
Connexins (Cx)TC# 1.A.24, or gap junction proteins, are structurally related transmembrane proteins that assemble to form vertebrate gap junctions. An entirely different family of proteins, the innexins, form gap junctions in invertebrates. Each ...
subunit.
[ A highly conserved phosphorylation site exists at the Threonine-139 position.] See multiple sequence alignment below.
File:TMEM229_b.jpg, Annotated diagram of the TMEM229b gene (with its 3 exons), mature mRNA and protein domains. Functional peptide is predicted to take the form of a connexin 4-pass transmembrane subunit (seen below).
Clinical relevance
Expression of the TMEM229B gene increases in several disease states including amelanotic skin melanoma, B-cell neoplasm, breast carcinoma
Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a Breast lump, lump in the breast, a change in breast shape, dimpling of the skin, Milk-rejection sign, milk rejection, fluid coming from the nipple, ...
, Burkitt's lymphoma
Burkitt lymphoma is a cancer of the lymphatic system, particularly B lymphocytes found in the germinal center. It is named after Denis Parsons Burkitt, the Irish surgeon who first described the disease in 1958 while working in equatorial Africa. ...
, colorectal adenocarcinoma, carcinoma, cutaneous T cell lymphoma, esophageal carcinoma
Esophageal cancer is cancer arising from the esophagus—the food pipe that runs between the throat and the stomach. Symptoms often include difficulty in swallowing and weight loss. Other symptoms may include pain when swallowing, a hoarse voic ...
, gastric carcinoma
Stomach cancer, also known as gastric cancer, is a cancer that develops from the lining of the stomach. Most cases of stomach cancers are gastric carcinomas, which can be divided into a number of subtypes, including gastric adenocarcinomas. Lymph ...
, glioblastoma
Glioblastoma, previously known as glioblastoma multiforme (GBM), is one of the most aggressive types of cancer that begin within the brain. Initially, signs and symptoms of glioblastoma are nonspecific. They may include headaches, personality ch ...
, liver carcinoma, lymphoma
Lymphoma is a group of blood and lymph tumors that develop from lymphocytes (a type of white blood cell). In current usage the name usually refers to just the cancerous versions rather than all such tumours. Signs and symptoms may include enlar ...
, melanoma
Melanoma, also redundantly known as malignant melanoma, is a type of skin cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin, but may rarely occur in the mouth, intestines, or eye ( ...
, small cell lung carcinoma
Small-cell carcinoma is a type of highly malignant cancer that most commonly arises within the lung, although it can occasionally arise in other body sites, such as the cervix, prostate, and gastrointestinal tract. Compared to non-small cell c ...
, T-cell acute lymphoblastic leukemia, thyroid carcinoma
Thyroid neoplasm is a neoplasm or tumor of the thyroid. It can be a benign tumor such as thyroid adenoma,Chapter 20 in: 8th edition. or it can be a malignant neoplasm (thyroid cancer), such as papillary thyroid cancer, papillary, follicular thyro ...
and Wilms' tumor
Wilms' tumor or Wilms tumor, also known as nephroblastoma, is a cancer of the kidneys that typically occurs in children, rarely in adults.; and occurs most commonly as a renal tumor in child patients. It is named after Max Wilms, the German surg ...
as found in several microarray
A microarray is a multiplex lab-on-a-chip. Its purpose is to simultaneously detect the expression of thousands of genes from a sample (e.g. from a tissue). It is a two-dimensional array on a solid substrate—usually a glass slide or silicon t ...
experiments. Over-expression of the TMEM229B gene has not been linked as a causal factor in any of these disease states.
References
{{DEFAULTSORT:Tmem229b
Proteins
Genes on human chromosome 14