Mannose-6-phosphate receptor binding protein 1 (M6PRBP1) is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
which in humans is encoded by the ''M6PRBP1''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
.
Its gene product, as well as the gene itself, is commonly known as TIP47.
Function
Mannose 6-phosphate receptor
The mannose 6-phosphate receptors (MPRs) are transmembrane glycoproteins that target enzymes to lysosomes in vertebrates.
Mannose 6-phosphate receptors bind newly synthesized lysosomal hydrolases in the trans-Golgi network (TGN) and deliver the ...
s (MPRs) deliver
lysosomal
A lysosome () is a membrane-bound organelle that is found in all mammalian cells, with the exception of red blood cells (erythrocytes). There are normally hundreds of lysosomes in the cytosol, where they function as the cell’s degradation cent ...
hydrolase
In biochemistry, hydrolases constitute a class of enzymes that commonly function as biochemical catalysts that use water to break a chemical bond:
:\ce \quad \xrightarrowtext\quad \ce
This typically results in dividing a larger molecule into s ...
from the
Golgi to
endosome
Endosomes are a collection of intracellular sorting organelles in eukaryotic cells. They are parts of the endocytic membrane transport pathway originating from the trans Golgi network. Molecules or ligands internalized from the plasma membra ...
s and then return to the Golgi complex. The protein encoded by this gene interacts with the cytoplasmic domains of both cation-independent and cation-dependent MPRs, and is required for endosome-to-Golgi transport. This protein also binds directly to the GTPase RAB9 (
RAB9A), a member of the
RAS oncogene family. The interaction with RAB9 has been shown to increase the affinity of this protein for its cargo.
The mannose-6-phosphate receptor-binding properties of TIP47 are disputed,
despite the designation of M6PRBP1 as TIP47's gene symbol. TIP47 protein is most commonly described in the scientific literature as a coat protein for
lipid droplet
Lipid droplets, also referred to as lipid bodies, oil bodies or adiposomes, are lipid-rich cellular organelles that regulate the storage and hydrolysis of neutral lipids and are found largely in the adipose tissue. They also serve as a reservoir ...
s.
TIP47 belongs to the
peripilin protein family and shares significant homology with the other genes of this family, including
perilipin
Perilipin, also known as lipid droplet-associated protein, perilipin 1, or PLIN, is a protein that, in humans, is encoded by the ''PLIN'' gene. The perilipins are a family of proteins that associate with the surface of lipid droplets. Phosphoryl ...
and
adipophilin.
Interactions
M6PRBP1 has been shown to
interact with both
Mannose 6-phosphate receptor
The mannose 6-phosphate receptors (MPRs) are transmembrane glycoproteins that target enzymes to lysosomes in vertebrates.
Mannose 6-phosphate receptors bind newly synthesized lysosomal hydrolases in the trans-Golgi network (TGN) and deliver the ...
s.
References
Further reading
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External links
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{{Vesicular transport proteins