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Structural highlights

Disease

[IMDH1_HUMAN] Defects in IMPDH1 are the cause of retinitis pigmentosa type 10 (RP10) [MIM:180105]. RP leads to degeneration of retinal photoreceptor cells. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well. RP10 inheritance is autosomal dominant.^{[1] [2] [3]} Defects in IMPDH1 are the cause of Leber congenital amaurosis type 11 (LCA11) [MIM:613837]. LCA11 is a severe dystrophy of the retina, typically becoming evident in the first years of life. Visual function is usually poor and often accompanied by nystagmus, sluggish or near-absent pupillary responses, photophobia, high hyperopia and keratoconus.^[4]

Function

[IMDH1_HUMAN] Catalyzes the conversion of inosine 5'-phosphate (IMP) to xanthosine 5'-phosphate (XMP), the first committed and rate-limiting step in the de novo synthesis of guanine nucleotides, and therefore plays an important role in the regulation of cell growth. Could also have a single-stranded nucleic acid-binding activity and could play a role in RNA and/or DNA metabolism. It may also have a role in the development of malignancy and the growth progression of some tumors.[HAMAP-Rule:MF_03156]

References

1. ↑ Kennan A, Aherne A, Palfi A, Humphries M, McKee A, Stitt A, Simpson DA, Demtroder K, Orntoft T, Ayuso C, Kenna PF, Farrar GJ, Humphries P. Identification of an IMPDH1 mutation in autosomal dominant retinitis pigmentosa (RP10) revealed following comparative microarray analysis of transcripts derived from retinas of wild-type and Rho(-/-) mice. Hum Mol Genet. 2002 Mar 1;11(5):547-57. PMID:11875049
2. ↑ Bowne SJ, Sullivan LS, Blanton SH, Cepko CL, Blackshaw S, Birch DG, Hughbanks-Wheaton D, Heckenlively JR, Daiger SP. Mutations in the inosine monophosphate dehydrogenase 1 gene (IMPDH1) cause the RP10 form of autosomal dominant retinitis pigmentosa. Hum Mol Genet. 2002 Mar 1;11(5):559-68. PMID:11875050
3. ↑ Bowne SJ, Sullivan LS, Mortimer SE, Hedstrom L, Zhu J, Spellicy CJ, Gire AI, Hughbanks-Wheaton D, Birch DG, Lewis RA, Heckenlively JR, Daiger SP. Spectrum and frequency of mutations in IMPDH1 associated with autosomal dominant retinitis pigmentosa and leber congenital amaurosis. Invest Ophthalmol Vis Sci. 2006 Jan;47(1):34-42. PMID:16384941 doi:10.1167/iovs.05-0868
4. ↑ Bowne SJ, Sullivan LS, Mortimer SE, Hedstrom L, Zhu J, Spellicy CJ, Gire AI, Hughbanks-Wheaton D, Birch DG, Lewis RA, Heckenlively JR, Daiger SP. Spectrum and frequency of mutations in IMPDH1 associated with autosomal dominant retinitis pigmentosa and leber congenital amaurosis. Invest Ophthalmol Vis Sci. 2006 Jan;47(1):34-42. PMID:16384941 doi:10.1167/iovs.05-0868
5. ↑ Burrell AL, Nie C, Said M, Simonet JC, Fernandez-Justel D, Johnson MC, Quispe J, Buey RM, Peterson JR, Kollman JM. IMPDH1 retinal variants control filament architecture to tune allosteric regulation. Nat Struct Mol Biol. 2022 Jan;29(1):47-58. doi: 10.1038/s41594-021-00706-2. Epub , 2022 Jan 10. PMID:35013599 doi:http://dx.doi.org/10.1038/s41594-021-00706-2