Cystin-1, also known as CYS1, is a novel cilia associated protein which in humans is encoded by the Cystin 1 gene on chromosome 2. The gene is highly expressed in the tissues of the kidneys. There are no known paralogs of Cystin-1 in humans, but has orthologs in mammals, birds, and some reptiles.
The Cystin 1 gene is found on the negative strand of chromosome 2 in humans, with the exact location at 2p25.1. It contains 3 exons, spanning 3045 base pairs.[1]
The gene is overwhelmingly expressed within tissues in the kidneys.[2] Lower expression levels are found in the ovaries, endometrium, lung, and gallbladder.
Gene expression levels are increased in the ovary of those who experience ovarian endometriosis.[3] There are also studies that connect the expression of Cystin to polycystic kidney disease,[4] but direct impact is unknown.
Cystin-1 consists of 158 amino acids and has a molecular weight of ~16.4kDa.[5]
There are not many known interacting proteins with Cystin-1. Table 1 shows just a few possible interactions.
| Gene | Abbreviation | Functions | |
| unc-119 lipid binding chaperone | UNC119 | Used to maintain localization | |
| N-myritstoyltransferase 1 | NMT1 | Used to maintain localization | |
| Phospholipase C gamme 1 | PLCG2 | Enable protein kinase activity | |
| Regulator of Telomere elongation helicase 1 | RTEL1 | Enables ATP binding and DNA helicase activity | |
| Epidermal growth factor receptor | EGFR | Biomarker for several diseases (including cancers) |
Based on protein interactions with UNC119B, Cystin-1 is predicted to be localized within the cilia of the cell. How this protein makes its way to the cilia is still unknown.
There are currently no known paralog of Cystin-1 within humans.
Orthologs of Cystin-1 were found in vertebrates, but not invertebrates.
| Genus and Species | Common Name | Taxonomy | Date of divergence from Humans (MYA) | NCBI Accession | Sequence identity to humans | Sequence Similarity to humans | ||
| Mammal | Homo sapiens | Humans | Primates | 0 | NP_001032237 | 100% | 100% | |
| Pongo abelii | Sumatran Orangutan | Primates | 18 | XP_024098426 | 92.40% | 93.70% | ||
| Monodon monoceros | Narwhal | Cetacea | 94 | XP_029088030.1 | 67.30% | 74.20% | ||
| Phyllostomus hastatus | Spear nosed bat | Chiroptera | 94 | XP_045700664.1 | 66.50% | 72% | ||
| Cervus canadensis | Elk | Artiodactyla | 94 | XP_043325302.1 | 65.40% | 71% | ||
| Acinonyx jubatus | Cheetah | Carnivora | 94 | XP_026933675.0 | 61.90% | 68.50% | ||
| Mus musculus | House Mouse | Rodentia | 87 | AAI39303.0 | 58.20% | 65.80% | ||
| Manis javanica | Sunda Pangolin | Pholidota | 94 | KAI5938697.0 | 27.10% | 29% | ||
| Reptilia | ||||||||
| Gopherus evgoodei | Goode's Thornscrub Tortiose | Testudines | 319 | XP_030411302.1 | 38% | 44.30% | ||
| Varanus komodoensis | Komodo Dragon | Squamata | 319 | XP_044275134.1 | 36.30% | 44% | ||
| Lacerta agilis | Sand Lizard | Squamata | 319 | XP_032998985.1 | 35.60% | 44.40% | ||
| Chelydra serpentina | Common Snapping Turtle | Testudines | 318 | KAG6933055 | 23% | 26.60% | ||
| Aves | ||||||||
| Vidua chalybeata | Village Indigo Brid | Passeriformes | 319 | XP_053794446.1 | 36% | 40.90% | ||
| Poecile atricapillus | Black Capped Chickadee | Passeriformes | 319 | XP_058691046.1 | 35.70% | 41.50% | ||
| Pipra filicauda | Wire-tailed Manakin | Passeriformes | 319 | XP_039240811.1 | 35.60% | 39.50% | ||
| Apus apus | Common Swift | Apodiformes | 319 | XP_051469776.1 | 35.40% | 42.30% |