EVA1C

EVA1C (Eva-1 Homolog C) is a transmembrane protein in humans (Homo sapiens) that is encoded by the EVA1C gene on Chromosome 21. The EVA1C protein is thought to be involved in herapin binding activity. In addition, the gene is thought to be associated with diseases such as X-Linked Intellectual Disability-Short Stature-Overweight Syndrome.

Aliases
B18, B19, C21orf63, C21orf64, FAM176C, PRED34, and SUE21 are aliases of the EVA1C gene.

Locus
EVA1C is located on the plus strand of Chromosome 21 (21q22.11). The span of the EVA1C gene is 103,394 bases (chr21:33,784,314-33,887,707).

Isoforms
EVA1C has 9 isoforms with EVA1C isoform X1 being the longest. This isoform is 441 amino acids in length.

Expression
EVA1C RNA is most highly expressed in the prostate, lungs, uterus, and heart. It is also highly expressed in the human stomach at 20 weeks postnatal, whereas it is most highly expressed in the heart at 11 weeks postnatal. Overall, it seems as though EVA1C RNA is most highly expressed in respiratory organs along with male and female reproductive organs. EVA1C was found to be expressed at low levels in the brain. However, using Allen Brain Atlas, EVA1C was found to be most highly expressed in the periaqueductal gray region of the midbrain in the house mouse (Mus musculus) brain.

Isoelectric point and molecular weight
The isoelectric point of the EVA1C protein in humans (Homo sapiens) is 6.5 pl and the molecular weight is 49 kDa. When comparing to its paralogs, EVA1A and EVA1B, EVA1C had the highest molecular weight and isoelectric point. This indicates that EVA1C is the largest protein.

Composition
The protein composition of EVA1C was found using EMBL-EBI SAPS. EVA1C consists of all 20 amino acids; with cysteine (C) being present in high amounts. The net charge of EVA1C was found to be lower than average. EVA1C has a negative charge cluster from 369 to 389 amino acids, which is where the disordered region is located. The transmembrane region was found to have a major hydrophobic region.

Regulation
EVA1C is predicted to have 6 post-translational modifications. Glycosylation can be found on the first half of the protein, while phosphorylation and ubiquitylation can be found on the second half of the protein. There are two of each type of post-translational modifications.

Interacting proteins
EVA1C has been shown to interact with AMN1, USE1, SLITRK3, ROBO3, FLRT3, DONSON, and POFUT2.

Orthologs
The orthologs of EVA1C were found using NCBI Homologene and sorted by median date of divergence found using TimeTree and sequence identity to the human protein was found using the EMBOSS Needle Tool. The species that has the most distantly related EVA1C gene to humans is EVA1C in a cartilaginous fish called the thorny skate (''Amblyraja radiata). '' The sequence identity of this species with humans is 45%. Mammals had an identity range of 87.8-98.6%,  Aves had an identity range of 51.3-63.4%, Reptilia had an identity range of 55.1-62%, Amphibians had an identity range of 51.7-58%, and Bony Fish had an identity range of 40.3-41.3%.

Paralogs
The paralogs of EVA1C are EVA1A (Eva-1 Homolog A) and EVA1B (Eva-1 Homolog B). The thorny skate (Amblyraja radiata) was found to be the most distant ortholog in EVA1A, EVA1B, and EVA1C. The divergence time of humans and the thorny skate is 464 million years ago.

Clinical significance
The EVA1C gene is located on the critical region of Down Syndrome in Chromosome 21. This syndrome is the result of individuals having an extra copy of Chromosome 21. Neurological and muscle impairments are experienced by individuals with a Down Syndrome diagnosis. An experiment that studied orthologs of Chromosome 21 in roundworms (Caenorhabditis elegans) found that EVA1C was one of the orthologs that was required for neuromuscular behaviors. The results of this experiment indicate that the EVA1C is a gene that underlies the phenotypes of Down Syndrome.