Mucolipin-3 also known as TRPML3 (transient receptor potential cation channel, mucolipin subfamily, member 3) is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

that in humans is encoded by the ''MCOLN3''

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

. It is a member of the small family of the

TRPML TRPML (transient receptor potential cation channel, mucolipin subfamily) comprises a group of three evolutionarily related proteins that belongs to the large family of transient receptor potential ion channels. The three proteins TRPML1, TRPML2 ...

channels, a subgroup of the large protein family of TRP ion channels.

Gene

In human, the ''MCOLN3'' gene resides on the short arm of

chromosome 1 Chromosome 1 is the designation for the largest human chromosome. Humans have two copies of chromosome 1, as they do with all of the autosomes, which are the non- sex chromosomes. Chromosome 1 spans about 249 million nucleotide base pairs, which ...

at 1p22.3. The gene is split in 12 exons, which entail the open reading frame of 1659 nucleotides. The encoded protein, TRPML3, has 553 amino acid with a predicted molecular weight of ≈64

kDa The dalton or unified atomic mass unit (symbols: Da or u) is a non-SI unit of mass widely used in physics and chemistry. It is defined as of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at re ...

. Computational analyses of the secondary structure predict the presence of six

transmembrane domain A transmembrane domain (TMD) is a membrane-spanning protein domain. TMDs generally adopt an alpha helix topological conformation, although some TMDs such as those in porins can adopt a different conformation. Because the interior of the lipid bi ...

s, an ion transport motif (PF00520) and a

transient receptor potential Transient receptor potential channels (TRP channels) are a group of ion channels located mostly on the plasma membrane of numerous animal cell types. Most of these are grouped into two broad groups: Group 1 includes TRPC ( "C" for canonical), TR ...

motif (PS50272). In the mouse, ''Mcoln3'', is located on the distal end of

chromosome 3 Chromosome 3 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 3 spans almost 200 million base pairs (the building material of DNA) and represents about 6.5 percent of the total DNA in ...

at cytogenetic band qH2. Human and mouse TRPML3 proteins share 91% sequence identity. All vertebrate species, for which a genomic sequence is available, harbor the ''MCOLN3'' gene. Homologs of ''MCOLN3'' are also present in the genome of insects (''

Drosophila melanogaster ''Drosophila melanogaster'' is a species of fly (the taxonomic order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the " vinegar fly" or "pomace fly". Starting with ...

''), nematodes ('' Caenorhabditis elegans''), sea urchin (''

Strongylocentrotus purpuratus ''Strongylocentrotus purpuratus'', the purple sea urchin, lives along the eastern edge of the Pacific Ocean extending from Ensenada, Mexico, to British Columbia, Canada. This sea urchin species is deep purple in color, and lives in lower int ...

'') and lower organisms including Hydra and Dictyostelium.

Expression

Function

TRPML3 is an inwardly-rectifying cation channel.

Genetics

Phenotypes

Mutations of the MCOLN3 gene in mice result in auditory

hair cell Hair cells are the sensory receptors of both the auditory system and the vestibular system in the ears of all vertebrates, and in the lateral line organ of fishes. Through mechanotransduction, hair cells detect movement in their environment. ...

death and

deafness Deafness has varying definitions in cultural and medical contexts. In medical contexts, the meaning of deafness is hearing loss that precludes a person from understanding spoken language, an audiological condition. In this context it is written ...

Ligands

; Agonists (channel activators) *

ML-SA1 ML-SA1 is a chemical compound which acts as an "agonist" (i.e. channel opener) of the TRPML family of calcium channels. It has mainly been studied for its role in activating TRPML1 channels, although it also shows activity at the less studied T ...

(non selective vs

TRPML1 Mucolipin-1 also known as TRPML1 (transient receptor potential cation channel, mucolipin subfamily, member 1) is a protein that in humans is encoded by the ''MCOLN1'' gene. It is a member of the small family of the TRPML channels, a subgroup of ...

) *

SN-2 SN-2 is a chemical compound which acts as an "agonist" (i.e. channel opener) for the TRPML3 calcium channel, with high selectivity for TRPML3 and no significant activity at the related TRPML1 and TRPML2 channels. It has demonstrated antiviral ...

(highly selective for TRPML3)

References

External links

* {{membrane-protein-stub