Apolipoproteins are protein components of plasma lipoproteins. Apolipoprotein A-I (ApoA1) promotes cholesterol efflux from tissues to the liver for excretion. ApoA1 is the major protein component of high density lipoprotein (HDL) in the plasma. It can function as a cofactor for lecithin cholesterolacyltransferase, which is responsible for the formation of most plasma cholesteryl esters. AI-BP (Apolipoprotein A-I-binding protein), also known as YjeF N-terminal domain-containing protein 1, is a 288 amino acid secreted protein that binds ApoA1, ApoA2 and HDL. Individuals with impaired renal function show an increased rate of AI-BP excretion, indicating that it is normally reabsorbed within the kidney tubules. AI-BP belongs to the YjeF N-terminal domain protein family, which includes proteins that are frequently involved in oogenesis and spermatogenesis. There are two isoforms of AI-BP that are produced as a result of alternative splicing events.
Function:
APOA1BP interacts with apolipoprotein A-I (apoA-I), the major apolipoprotein of high-density lipoproteins (HDLs). It is secreted into some bodily fluids, and its synthesis and secretion are stimulated in vitro by incubating cells with apoA-I.
Subunit:
Homodimer (By similarity). Interacts with APOA1 and APOA2.
Subcellular Location:
Secreted
Tissue Specificity:
Ubiquitously expressed, with highest levels in kidney, heart and liver. Present in cerebrospinal fluid and urine but not in serum from healthy patients. Present in serum of sepsis patients (at protein level).
Post-translational modifications:
Undergoes physiological phosphorylation during sperm capacitation, downstream to PKA activation (By similarity).
Similarity:
Belongs to the nnrE/AIBP family.
Contains 1 YjeF N-terminal domain.
SWISS:
Q8NCW5
Gene ID:
12848
Database links:
Entrez Gene: 12848 Human
Entrez Gene: 246703 Mouse
Entrez Gene: 780405 Pig
Entrez Gene: 295229 Rat
Omim: 608862 Human
SwissProt: Q6QRN6 Cow
SwissProt: E2QRY6 Dog
SwissProt: Q8NCW5 Human
SwissProt: Q8K4Z3 Mouse
SwissProt: Q0PIT9 Pig
SwissProt: B0BNM1 Rat
Unigene: 52864 Human
Unigene: 205996 Mouse
Unigene: 14886 Rat
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