Ankycorbin is an ankyrin repeat and coiled-coil domain containing protein that in humans is encoded by the RAI14 gene. It is expressed in a variety of human tissues and is thought to play a role in actin regulation of ectoplasmic specialization, establishment of sperm polarity and sperm adhesion. It may also promote the integrity of Sertoli cell tight junctions at the blood testis barrier.

Rai14
Identifiers
Aliases1700008J19Rik1700020L11RikAnkycorbinNorpegmKIAA1334retinoic acid induced 14
External IDsHomoloGene: 9199; GeneCards: [1]; OMA:- orthologs
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_001166408
NM_030690
NM_001356534

n/a

RefSeq (protein)

NP_001159880
NP_109615
NP_001343463

n/a

Location (UCSC)Chr 15: 10.57 – 10.71 Mbn/a
PubMed search[1]n/a
Wikidata
View/Edit Human

Gene

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Location

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RAI14 contains 15 exons and is located on the plus strand of chromosome number 5 at position 5p13.2. It spans 5,068 base pairs from position 34,656,328 to 34,832,612.[2]

Gene Neighborhood

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Genes TTC23L and LOC105374721 neighbor RAI14 on chromosome 5.

Expression

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RAI14 is expressed within a wide range of human tissues. Some areas of the highest expression by TPM (transcripts per million) include tissues of the endometrium, smooth muscle, cervix, cervix, testis, and spleen. Within the human brain, RAI14 expression is abundant in the area around the brain stem and medulla. The highest expression levels came from the myelencephalon, a region of the embryonic brain that would later become the medulla oblongata.[3]

 
RAI14 protein expression within human tissues

Homology

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Paralogs

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RAI14 does not have any paralogs.

Orthologs

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Most of the entire sequence of the ankycorbin protein is well conserved between the majority of mammals and vertebrates.[4] More distantly related orthologs, such as sharks, begin to lose similarity and become less conserved in the C-terminus end of the protein. Ankycorbin is not well conserved within invertebrates, such as coral, at all. The latter half of the protein is largely missing and the only portion that retains some semblance of conservation is the area near the N-terminus that is associated with the ankyrin repeat domain.

Table of RAI14 Orthologs
Genus and Species Common Name Date of Divergence

(from Homo sapiens)

NCBI Accession

Number

Sequence Length

(Amino Acids)

Sequence

Identity

Homo sapiens Human NP_001138992.1 980 100%
Castor canadensis North American Beaver 88 MYA XP_020026070.1 980 92%
Delphinapterus leucas Beluga Whale 94 MYA XP_022455298.1 980 90%
Pelecanus crispus Dalmatian pelican 320 MYA XP_009485865.1 977 69%
Python bivittatus Burmese python 320 MYA XP_007432514.1 992 66%
Xenopus laevis African clawed frog 353 MYA XP_018100022.1 971 53%
Rhincodon typus Whale Shark 465 MYA XP_020373853.1 719 46%
Stylophora pistillata Coral 685 MYA XP_022783988.1 653 31%
 
An image depicting RAI14 expression levels within the human brain

Protein

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Transcripts

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Ankycorbin has four different isoforms (A, B, C, and D) with most isoforms containing one or more splice variants that mainly differ in the 5' UTR. Isoform D is the longest known isoform at 983 amino acids in length, however isoform A (980 amino acids) is the most predominant form of the protein.[5]

General Properties

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The RAI14 protein has a predicted weight of 110.0 kDal and an isoelectric point of 5.87. It's also predicted to have glutamine rich region between nucleotides 914-978 and is otherwise rich in lycine, glutamate, and serine while being poor in glycine and phenylalanine.[6] It is a soluble protein.[7]

Structure and Domains

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Ankycorbin contains an ankyrin repeat region located near the N-terminus[8] that consists of 6 ankyrin repeats. The protein is predominantly composed of alpha helices and coiled-coil domains with no predicted beta-sheet structures.

Post Translational Modifications

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RAI14 is a highly phosphorylated protein with hundreds of predicted phosphorylation sites. It is predicted to be a nuclear protein and contains 3 nuclear localization signals.

Function

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RAI14 is predicted to play a role in cell-cell adhesion sites, particularly the cell-cell interactions of Sertoli cells from within the testis. Sertoli cells are involved in the creation of the blood testis barrier and provides a specialized, protected environment within the seminiferous tubules of the testis for germ cell development.[9]

References

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  1. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  2. ^ "RAI14 retinoic acid induced 14 [ Homo sapiens (human) ]". February 4, 2018. Retrieved February 19, 2018.
  3. ^ "Allen Brain Atlas: Human Brain". Allen Brain Atlas.
  4. ^ "NCBI: Protein Blast". Retrieved March 2, 2018.
  5. ^ "ankycorbin isoform a [Homo sapiens]". NCBI. October 2, 2017. Retrieved February 19, 2018.
  6. ^ "SAPS". EMBL-EBI.
  7. ^ Hirikawa, T.; Boon-Chieng, S.; Mitaku, S. "SOSUI: classification and secondary structure prediction system for membrane proteins".
  8. ^ "PSORT II". PSORT: Predicting of Protein Sorting and Localization Sites in Amino Acid Sequences. Retrieved April 27, 2018.
  9. ^ Martin CM, Kleid JJ (2015). "Pseudofusion beats masquerading as pacemaker failure". Journal of Electrocardiology. 7 (2): 179–81. doi:10.1016/S0022-0736(74)80028-2. PMID 4822540.