Molecular diversity and evolution of the large lipid transfer protein superfamily.
Level 5 - mechanism / opinion, no new human data
Level 5 by design analogy: narrative review and evolutionary sequence/phylogenetic analysis without clinical or human experimental trial data.
PubMed 17148551 · doi:10.1194/jlr.R600028-JLR200
What was done
The authors conducted structural, sequence, and phylogenetic analyses across animal genomes to evaluate the evolutionary history, structural variation, and functional diversification of the large lipid transfer protein (LLTP) superfamily (including apolipoprotein B, vitellogenin, and microsomal triglyceride transfer protein [MTP]).
What was found
The abstract provides no quantitative metrics or sample sizes. Qualitatively, LLTPs were identified as unique to animals and traced back to the earliest multicellular organisms. Analyses classified the superfamily into three primary families: apoB-like, vitellogenin-like, and ubiquitous MTP-like LLTPs, alongside two novel LLTPs recognized in insects. Substantial structural variations were documented in major lipid-binding modules (amphipathic secondary structure clusters, protein modifications, and domain sizing), reflecting gene duplication and neofunctionalization extending beyond basic circulatory lipid transport.
Why it matters
Understanding the structural and evolutionary trajectories of lipid transfer proteins clarifies how circulatory lipid carriers diversified and identifies structural features that may inform strategies for manipulating lipid transport mechanisms.
Limits
The abstract reports purely qualitative evolutionary and structural deductions without quantitative sequence alignments, sample numbers of species or sequences analyzed, or direct experimental functional validation.
Cited by
- contradicts Most animal species do not have ApoB and do not require LDL.