ATP binding cassette subfamily D member 4

Normal function

The ABCD4 gene provides instructions for making a protein that is involved in the conversion of vitamin B12 (also known as cobalamin) into one of two molecules, adenosylcobalamin (AdoCbl) or methylcobalamin (MeCbl). AdoCbl is required for the normal function of an enzyme known as methylmalonyl CoA mutase. This enzyme helps break down certain protein building blocks (amino acids), fat building blocks (fatty acids), and cholesterol. AdoCbl is called a cofactor because it helps methylmalonyl CoA mutase carry out its function. MeCbl is also a cofactor, but for an enzyme known as methionine synthase. This enzyme converts the amino acid homocysteine to another amino acid, methionine. The body uses methionine to make proteins and other important compounds.

The ABCD4 protein is found in the membrane that surrounds cell structures called lysosomes. Lysosomes are compartments within cells in which enzymes digest and recycle materials. In the lysosomal membrane, the ABCD4 protein interacts with another protein called LMBD1 (produced from the LMBRD1 gene). Together, these two proteins transport vitamin B12 out of lysosomes, making it available for further processing into AdoCbl and MeCbl.

Conditions referring to this gene or chromosome

• Methylmalonic acidemia with homocystinuria

Other names

69 kDa peroxisomal ABC-transporter

ABC41

ATP-binding cassette sub-family D member 4

ATP-binding cassette, sub-family D (ALD), member 4

EST352188

MAHCJ

P70R

P79R

peroxisomal membrane protein 69

PMP69

PMP70-related protein

PXMP1-L

PXMP1L