4jhp is a lipid binding protein. It is composed of two macromolecules described as retinal rod rhodopsin sensitive cGMP 3',5’cyclic phosphodiesterase subunit delta as well as X-linked retinitis pigmentosa GTPase regulator [1]. The retinitis pegmentosa GTPase regulator, RPGR, may be mutated causing severe eye disease. It is also located in a region considered a ciliary zone [2]. The European Molecular Biology Organization reports proposes that RPGR is being recruited to place lapidated cargo into the cilia. Oxford academic also has an article about ciliary trafficking defects. Examples given for ciliopathies it may cause are Joubert Syndrome, Bardet-Biedel Syndrome, and forms of retinitis pigmentosa [2].
Structure
RPGR consist of 28 beta sheets and 4 alpha helices. It also contains a glutamate rich region [1].
Function
RPGR essentially provides normal vision. This protein is known to localize the outer segments of rod photoreceptors. It plays a role in ciliogenesis, photoreceptor integrity, and spermatogenesis. The cilia are fingerlike projections from the cell that aid in its movement [5]. It has the ability to regulate the cilia by regulating the actin stress filaments [5]. It is localized in the Golgi apparatus.
Related Disease
Ciliopathies are caused by defects to the cilia. Ciliopathies include kidney disease, nephronophtisis, Bardet–Biedl syndrome (BBS) and retinal degeneration syndromes [3]. Retinitis pigmentosa is an eye disease that cause the photoreceptors cells to degenerate [3]. More than 300 mutations to the RPGR may cause retinitis pigmentosa and make up 70% of the occurrences [3]. These mutations usually cause the protein to be shortened and malfunction. Once there is degeneration, night blindness may occur and eventually complete loss of vision. This disease may lead to other ciliopathy phenotypes such as respiratory infection, hearing defects, and abnormal sperm. Retinitis pigmentosa GTPase regulator is also connected to a more severe disease, X-linked retinitis pigmentosa.
Genomic Location
Chromosome: X
Size: 58,402 bases & 1020 amino acids
Orientation: minus strand [4]
Orthologs
Mouse (Mus musculus) with a similarity of 75.75n, Chicken (Gallus gallus) with a similarity of 48a, Lizard (Anolis carolinensis) with a similarity of 76a, and Zebrafish (Danio rerio) with a similarity of 60.49n and 23a. [4]
Expression In Human Tissues
Expression can be seen in major tissues within the immune, nervous, muscle, internal, secretory, and reproductive systems. The tissues that show expression within the immune system are the bone marrow, whole blood, lymph nodes, and thymus. The tissues within the nervous system are the brain, cerebellum, retina, and the spinal cord. The tissues within the muscles are the heart, smooth muscle, and skeletal muscle. The internal tissues consist of the colon, adipocyte, kidney, liver, and lung. The tissues within the secretory are the pancreas, thyroid, adrenal gland, salivary gland, and the skin. Finally, the tissues affected within the reproductive system are the ovary, uterus, placenta, prostate, and testis. [4]
Structural highlights
While this structure of 4JHP consist of two macromolecules, I am only focusing of the portion made up to RPGR (retinitis pigmentosa GTPase regulator).
This is a sample scene created with SAT to by Group, and another to make of the protein, and another to make of the protein.
