| Structural highlights
Disease
MCLN1_HUMAN Mucolipidosis type 4. The disease is caused by mutations affecting the gene represented in this entry.
Function
MCLN1_HUMAN Cation channel probably playing a role in the endocytic pathway and in the control of membrane trafficking of proteins and lipids. Could play a major role in Ca(2+) transport regulating lysosomal exocytosis.[1] [2]
Publication Abstract from PubMed
The activities of organellar ion channels are often regulated by Ca2+ and H+, which are present in high concentrations in many organelles. Here we report a structural element critical for dual Ca2+/pH regulation of TRPML1, a Ca2+-release channel crucial for endolysosomal function. TRPML1 mutations cause mucolipidosis type IV (MLIV), a severe lysosomal storage disorder characterized by neurodegeneration, mental retardation and blindness. We obtained crystal structures of the 213-residue luminal domain of human TRPML1 containing three missense MLIV-causing mutations. This domain forms a tetramer with a highly electronegative central pore formed by a novel luminal pore loop. Cysteine cross-linking and cryo-EM analyses confirmed that this architecture occurs in the full-length channel. Structure-function studies demonstrated that Ca2+ and H+ interact with the luminal pore and exert physiologically important regulation. The MLIV-causing mutations disrupt the luminal-domain structure and cause TRPML1 mislocalization. Our study reveals the structural underpinnings of TRPML1's regulation, assembly and pathogenesis.
Structural basis of dual Ca2+/pH regulation of the endolysosomal TRPML1 channel.,Li M, Zhang WK, Benvin NM, Zhou X, Su D, Li H, Wang S, Michailidis IE, Tong L, Li X, Yang J Nat Struct Mol Biol. 2017 Mar;24(3):205-213. doi: 10.1038/nsmb.3362. Epub 2017, Jan 23. PMID:28112729[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ LaPlante JM, Falardeau J, Sun M, Kanazirska M, Brown EM, Slaugenhaupt SA, Vassilev PM. Identification and characterization of the single channel function of human mucolipin-1 implicated in mucolipidosis type IV, a disorder affecting the lysosomal pathway. FEBS Lett. 2002 Dec 4;532(1-2):183-7. PMID:12459486
- ↑ Raychowdhury MK, Gonzalez-Perrett S, Montalbetti N, Timpanaro GA, Chasan B, Goldmann WH, Stahl S, Cooney A, Goldin E, Cantiello HF. Molecular pathophysiology of mucolipidosis type IV: pH dysregulation of the mucolipin-1 cation channel. Hum Mol Genet. 2004 Mar 15;13(6):617-27. Epub 2004 Jan 28. PMID:14749347 doi:http://dx.doi.org/10.1093/hmg/ddh067
- ↑ Li M, Zhang WK, Benvin NM, Zhou X, Su D, Li H, Wang S, Michailidis IE, Tong L, Li X, Yang J. Structural basis of dual Ca2+/pH regulation of the endolysosomal TRPML1 channel. Nat Struct Mol Biol. 2017 Mar;24(3):205-213. doi: 10.1038/nsmb.3362. Epub 2017, Jan 23. PMID:28112729 doi:http://dx.doi.org/10.1038/nsmb.3362
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