apolipoprotein B48 (apoB48)
Jump to navigation
Jump to search
Function
- by analogy to apo B100, it is suggested that apo B48 may play a role in chylomicron transport
- binds to apo B-48 receptor, distinct from apo B-100 receptor (LDL receptor)
Structure
- apo B48 consists of the N-terminal 2152 residues of Apo B100
- it does not include recognition site for LDL receptor
RNA editing
- modified positions=2180
- the stop codon (UAA) at position 2180 is created by RNA editing
- apo B-48, derived from the fully edited RNA, is produced only in the intestine & is found in chylomicrons
- apo B-48 is a shortened form of apo B-100 which lacks the LDL-receptor region
Expression
- apo B48 is formed via intestine-specific post-transcriptional modification of the ApoB gene transcript (mRNA editing) to generate new stop codon within the transcribed region
Pathology
- normally, very little B-48 is found in plasma of fasting individuals; however, in persons with defects in chylomicron remnant clearance (e.g. chronic renal failure), levels of B-48 are increased; this would imply role of the kidney in chylomicron remnant clearance