Intraflagellar transport protein 88 homolog is a protein that is encoded by the IFT88 gene. [5] [6]
This gene encodes a member of the tetratrico peptide repeat (TPR) family. Mutations of a similar gene in mouse can cause polycystic kidney disease. Two transcript variants encoding distinct isoforms have been identified for this gene. [6] In 2012 a mutation was found to be responsible for a novel form of ciliopathy and anosmia in humans capable of remedy in mice by adenoviral mediated gene therapy. [7]
IFT88 has been shown to interact with BAT2 and WDR62. [8] [9] WDR62 is required for IFT88 localization to the cilia basal body and the cilia axoneme. [10]
Bardet–Biedl syndrome (BBS) is a ciliopathic human genetic disorder that produces many effects and affects many body systems. It is characterized by rod/cone dystrophy, polydactyly, central obesity, hypogonadism, and kidney dysfunction in some cases. Historically, slower mental processing has also been considered a principal symptom but is now not regarded as such.
Intraflagellar transport (IFT) is a bidirectional motility along axoneme microtubules that is essential for the formation (ciliogenesis) and maintenance of most eukaryotic cilia and flagella. It is thought to be required to build all cilia that assemble within a membrane projection from the cell surface. Plasmodium falciparum cilia and the sperm flagella of Drosophila are examples of cilia that assemble in the cytoplasm and do not require IFT. The process of IFT involves movement of large protein complexes called IFT particles or trains from the cell body to the ciliary tip and followed by their return to the cell body. The outward or anterograde movement is powered by kinesin-2 while the inward or retrograde movement is powered by cytoplasmic dynein 2/1b. The IFT particles are composed of about 20 proteins organized in two subcomplexes called complex A and B.
Agouti-signaling protein is a protein that in humans is encoded by the ASIP gene. It is responsible for the distribution of melanin pigment in mammals. Agouti interacts with the melanocortin 1 receptor to determine whether the melanocyte produces phaeomelanin, or eumelanin. This interaction is responsible for making distinct light and dark bands in the hairs of animals such as the agouti, which the gene is named after. In other species such as horses, agouti signalling is responsible for determining which parts of the body will be red or black. Mice with wildtype agouti will be grey, with each hair being partly yellow and partly black. Loss of function mutations in mice and other species cause black fur coloration, while mutations causing expression throughout the whole body in mice cause yellow fur and obesity.
Fibrocystin is a large, receptor-like protein that is thought to be involved in the tubulogenesis and/or maintenance of duct-lumen architecture of epithelium. FPC associates with the primary cilia of epithelial cells and co-localizes with the Pkd2 gene product polycystin-2 (PC2), suggesting that these two proteins may function in a common molecular pathway.
Polycystin 1 (PC1) is a protein that in humans is encoded by the PKD1 gene. Mutations of PKD1 are associated with most cases of autosomal dominant polycystic kidney disease, a severe hereditary disorder of the kidneys characterised by the development of renal cysts and severe kidney dysfunction.
Polycystin-2(PC2) is a protein that in humans is encoded by the PKD2 gene.
WD repeat-containing protein 36 is a protein that in humans is encoded by the WDR36 gene.
Nephrocystin-4 is a protein that in humans is encoded by the NPHP4 gene.
Intraflagellar transport protein 57 homolog is a protein that in humans is encoded by the IFT57 gene.
WD repeat-containing protein 62 is a protein that in humans is encoded by the WDR62 gene.
Kinesin-like protein KIF17 is a protein that in humans is encoded by the KIF17 gene. KIF17 and its close relative, C. elegans OSM-3, are members of the kinesin-2 family of plus-end directed microtubule-based motor proteins. In contrast to heterotrimeric kinesin-2 motors, however, KIF17 and OSM-3 form distinct homodimeric complexes. Homodimeric kinesin-2 has been implicated in the transport of NMDA receptors along dendrites for delivery to the dendritic membrane, whereas both heterotrimeric and homodimeric kinesin-2 motors function cooperatively in anterograde intraflagellar transport (IFT) and cilium biogenesis.
Intraflagellar transport protein 20 homolog is a protein that in humans is encoded by the IFT20 gene. The gene is composed of 6 exons and is located on human chromosome 17p11.1. This gene is expressed in human brain, lung, kidney and pancreas, and lower expression were also detected in human placenta, liver, thymus, prostate and testis.
Polycystic kidney disease is a genetic disorder in which the renal tubules become structurally abnormal, resulting in the development and growth of multiple cysts within the kidney. These cysts may begin to develop in utero, in infancy, in childhood, or in adulthood. Cysts are non-functioning tubules filled with fluid pumped into them, which range in size from microscopic to enormous, crushing adjacent normal tubules and eventually rendering them non-functional as well.
Polycystic kidney disease 2-like 2 protein (PKD2L2) also known as transient receptor potential polycystic 5 (TRPP5) is a protein that in humans is encoded by the PKD2L2 gene.
Intraflagellar transport protein 81 homolog is a protein that in humans is encoded by the IFT81 gene. Together with IFT74/72 it forms a core complex to build IFT particles which are required for cilium formation. Additionally, it interacts with basal body components as CEP170 which regulates the disassembly of the cilium.
Intraflagellar transport protein 74 homolog (IFT74), also known as coiled-coil domain-containing protein 2 (CCDC2) and capillary morphogenesis gene 1 protein (CMG1), is a protein that in humans is encoded by the IFT74 gene.
Intraflagellar transport protein 80 homolog (IFT80), also known as WD repeat-containing protein 56, is a protein that in humans is encoded by the IFT80 gene.
A BBSome is a protein complex that operates in primary cilia biogenesis, homeostasis, and intraflagellar transport (IFT). The BBSome recognizes cargo proteins and signaling molecules like G-protein coupled receptors (GPCRs) on the ciliary membrane and helps transport them to and from the primary cilia. Primary cilia are nonmotile microtubule projections that function like antennae and are found in many types of cells. They receive various environmental signals to aid the cell in survival. They can detect photons by concentrating rhodopsin, a light receptor that converts photons into chemical signals, or odorants by concentrating olfactory receptors on the primary cilia surface. Primary cilia are also meaningful in cell development and signaling. They do not contain any way to make proteins within the primary cilia, so the BBSome aids in transporting essential proteins to, from, and within the cilia. Examples of cargo proteins that the BBSome is responsible for ferrying include smoothened, polycystic-1 (PC1), and several G-Protein coupled receptors (GPCRs) like somatostatin receptors (Sstr3), melanin-concentrating hormone receptor 1 (Mchr1), and neuropeptide Y2 receptor.
Sensenbrenner syndrome is a rare multisystem disease first described by Judith A. Sensenbrenner in 1975. It is inherited in an autosomal recessive fashion, and a number of genes appear to be responsible. Three genes responsible have been identified: intraflagellar transport (IFT)122 (WDR10), IFT43—a subunit of the IFT complex A machinery of primary cilia, and WDR35
IFT140, Intraflagellar transport 140 homolog, is a protein that in humans is encoded by the IFT140 gene. The gene product forms a core component of IFT-A complex which is indipensible for retrograde intraflagellar transport within the primary cilium.