| PRR21 | |||||||||||||||||||||||||||||||||||||||||||||||||||
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| Identifiers | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Aliases | PRR21 , Proline-rich protein 21, proline rich 21 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| External IDs | HomoloGene: 135702 GeneCards: PRR21 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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| Wikidata | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Proline-rich protein 21 (PRR21) is a protein of the family of proline-rich proteins. It is encoded by the PRR21 gene, which is found on human chromosome 2, band 2q37.3. [2] The gene exists in several species, both vertebrates and invertebrates, including humans. [3] However, the protein have few conserved regions among species.
PRR21 consists of 389 amino acids or 1170 base pairs, all found within one exon. Like other proline-rich proteins, it contains a repeated sequence of amino acids that contains several proline residues. [4] The tandemly repeated sequence of PRR21 is 28 amino acids long and is repeated in full 11 times, with few variations. A logo displaying the variances of the repeat is shown below. [5] The repeat constitute almost the entire protein, except for the very beginning and a short tail.
Many single-nucleotide polymorphisms (SNPs) are predicted for the gene, and several of these cause missense mutations. [6] This allows for personal variances within the population, and contribution to the "uniqueness" of each individual. [7]
PRR21 has 28 possible phosphorylation sites. [8] These follow the patterns of the repeated sequence. [9] 22 out of 28 phosphorylation sites occur at serines at positions 9 and 24 in the repeat, both of which are highly conserved. Though, these serines can be changed by SNPs. [10] Phosphorylation generally either activates or inactivates a protein. [11] The protein has a no potential GPI-modification sites. [12] PRR21 is not predicted to interact with any other proteins.
PRR21 have no paralogs, and few orthologs. The orthologs are poorly conserved, as proline-rich proteins lack the need for specificity. [4] Most important is that they have a loose structure and contain many prolines. The repeats often work as spacers only to make the protein big enough to interact with other proteins. [4] Thus, orthologs often look dissimilar.
There is 99.97% likelihood that PRR21 enters the mitochondria. [13] PRR21 may be involved in stress responses that are related to phosphorylation of mitochondrial proteins. [14] The gene is ubiquitously expressed, as nearly all eukaryotic cells contain mitochondria. [15] PRR21 may be a salivary protein, as the tandemly repeated sequence constitute almost the entire protein, which is a common feature of salivary proline-rich proteins. [4]
There are several kinds of proline-rich proteins, which can include either repetitive short sequences or tandemly repeated sequences. They have in common that the repeats, and the repeats only, contain unusual amounts of proline. They have a loose structure, which is caused by several features; the prolines have a shape that causes to chain to turn, and especially prevents alpha helices. Also, the proteins contain many positively charged residues that repel each other. This results in loose proteins that are suitable as binding proteins. These binding interactions can be hydrophobic interactions as proline-rich proteins tend to have exposed hydrophobic regions. The prolines themselves work as additional binding sites for hydrogen bonds by being strong hydrogen acceptors. [4]
MORN1 containing repeat 1, also known as Morn1, is a protein that in humans is encoded by the MORN1 gene.
Proline-rich 12 (PRR12) is a protein of unknown function encoded by the gene PRR12.
Protein FAM46B also known as family with sequence similarity 46 member B is a protein that in humans is encoded by the FAM46B gene. FAM46B contains one protein domain of unknown function, DUF1693. Yeast two-hybrid screening has identified three proteins that physically interact with FAM46B. These are ATX1, PEPP2 and DAZAP2.
RUN and FYVE domain containing 2 (RUFY2) is a protein that in humans is encoded by the RUFY2 gene. The RUFY2 gene is named for two of its domains, the RUN domain and FYVE domains. RUFY2 is a member of the RUFY family of proteins that include RUFY1, RUFY2, RUFY3, and RUFY4. RUFY2 protein has a dynamic role in endosomal membrane trafficking.
Coiled-coil domain containing 130 is a protein that in humans is encoded by the CCDC130 gene. It is part of the U4/U5/U6 tri-snRNP in the U5 portion. This tri-snRNP comes together with other proteins to form complex B of the mature spliceosome. The mature protein is approximately 45 kilodaltons (kDa) and is extremely hydrophilic due to the abnormally high number of charged and polar amino acids. CCDC130 is a highly conserved protein, it has orthologous genes in some yeasts and plants that were found using nucleotide and protein versions of the basic local alignment search tool (BLAST) from the National Center for Biotechnology Information. GEO profiles for CCDC130 have shown that this protein is ubiquitously expressed, but the highest levels of expression are found in T-lymphocytes.
Glutamine Serine Rich Protein 1 or QSER1 is a protein encoded by the QSER1 gene.
Coiled-coil domain containing 109B (CCDC109B) is a potential calcium uniporter protein found in the membrane of human cells and is encoded by the CCDC109B gene. While CCDC109B is a transmembrane protein it is unclear if it is located within the cell membrane or mitochondrial membrane.
Family with Sequence Similarity 203, Member B (FAM203B) is a protein encoded by the FAM203B gene (8q24.3) in humans. While FAM203B is only found in humans and possibly non-human primates, its paralog, FAM203A, is highly conserved. The FAM203B protein contains two conserved domains of unknown function, DUF383 and DUF384, and no transmembrane domains. This protein has no known function yet, although the homolog of FAM203A in Caenorhabditis elegans (Y54H5A.2) is thought to help regulate the actin cytoskeleton.
Coiled Coil Domain Containing protein 42B, also known as CCDC42B, is a protein encoded by the protein-coding gene CCDC42B.
Transmembrane protein 251, also known as C14orf109 or UPF0694, is a protein that in humans is encoded by the TMEM251 gene. One notable feature of this protein is the presence of proline residues on one of its predicted transmembrane domains., which is a determinant of the intramitochondrial sorting of inner membrane proteins.
Intermediate filament family orphan 1 is a protein that in humans is encoded by the IFFO1 gene. IFFO1 has uncharacterized function and a weight of 61.98 kDa. IFFO1 proteins play an important role in the cytoskeleton and the nuclear envelope of most eukaryotic cell types.
PRP36 is an extracellular protein in Homo sapiens that is encoded by the PRR36 gene that contains a domain of unknown function, DUF4596, towards the C terminus of the protein. The function of PRP36 is unknown, but high gene expression has been observed in various regions of the brain such as the prefrontal cortex, cerebellum, and the amygdala. PRP36 has one alias: Putative Uncharacterized Protein FLJ22184.
PRR29 is a protein encoded by the PRR29 gene located in humans on chromosome 17 at 17q23.
PRR32 is a protein that in humans is encoded by the CXorf64 gene. It was also found that the homologs of the PRR32 gene is conserved in chimpanzee, Rhesus monkey, dog, cow, mouse, and rat. It was also found through ncbi that 82 organisms have orthologs with human gene PRR323.
Proline-rich protein 30 is a protein in humans that is encoded for by the PRR30 gene. PRR30 is a member in the family of Proline-rich proteins characterized by their intrinsic lack of structure. Copy number variations in the PRR30 gene have been associated with an increased risk for neurofibromatosis.
Coiled-coil domain containing 166 is a protein that in humans is encoded by the CCDC166 gene. Its function is currently unknown. It contains a coiled-coil domain, hence the current origin of its name. It is primarily expressed in the testes.
Transmembrane protein 171 (TMEM171) is a protein that in humans is encoded by the TMEM171 gene.
C2orf16 is a protein that in humans is encoded by the C2orf16 gene. Isoform 2 of this protein is 1,984 amino acids long. The gene contains 1 exon and is located at 2p23.3. Aliases for C2orf16 include Open Reading Frame 16 on Chromosome 2 and P-S-E-R-S-H-H-S Repeats Containing Sequence.
Transmembrane protein 125 is a protein that, in humans, is encoded by the TMEM125 gene. It has 4 transmembrane domains and is expressed in the lungs, thyroid, pancreas, intestines, spinal cord, and brain. Though its function is currently poorly understood by the scientific community, research indicates it may be involved in colorectal and lung cancer networks. Additionally, it was identified as a cell adhesion molecule in oligodendrocytes, suggesting it may play a role in neuron myelination.
Chromosome 13 Open Reading Frame 46 is a protein which in humans is encoded by the C13orf46 gene. In humans, C13orf46 is ubiquitously expressed at low levels in tissues, including the lungs, stomach, prostate, spleen, and thymus. This gene encodes eight alternatively spliced mRNA transcript, which produce five different protein isoforms.
