Apolipoprotein L1 (APOL1): Consideration of Molecular Evolution, Interaction with APOL3, and Impact of Splice Isoforms Advances Understanding of Cellular and Molecular Mechanisms of Cell Injury

The Apolipoprotein L1 (APOL1) innate immunity gene product represents the sole member of the APOL gene family in humans capable of secretion into circulation, thereby mediating the trypanolysis of <i>T. brucei brucei</i>. Gain-of-function variants of the APOL1 gene originated and spread...

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Main Authors: Razi Khalaila, Karl Skorecki
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Cells
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Online Access:https://www.mdpi.com/2073-4409/14/13/1011
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author Razi Khalaila
Karl Skorecki
author_facet Razi Khalaila
Karl Skorecki
author_sort Razi Khalaila
collection DOAJ
description The Apolipoprotein L1 (APOL1) innate immunity gene product represents the sole member of the APOL gene family in humans capable of secretion into circulation, thereby mediating the trypanolysis of <i>T. brucei brucei</i>. Gain-of-function variants of the APOL1 gene originated and spread among human population groups to extend APOL1’s protective capacity to include also serum-resistant subspecies, such as <i>T. brucei gambiense</i> (S342G known as APOL1-G1) and <i>T. brucei rhodesiense</i> (N388_Y389del known as APOL1-G2). The biochemical pathways underlying the lytic activity of these evolutionary favored mutations against bloodstream trypanosomes have been elucidated with remarkable precision. However, the intricate molecular mechanisms by which such variants confer an increased susceptibility to renal cellular injury and consequent kidney disease remain incompletely defined. In the absence of a consistent mechanistic explanation for differential kidney injury, we propose pursuing three interrelated avenues of investigation informed by prior epidemiological and mechanistic evidence linking them to APOL1’s cytotoxicity: (1) Molecular evolution of APOL1 haplotypes in human populations, (2) APOL1 splicing and consequent splice isoforms, (3) Interaction of APOL1 with other APOL gene family members, prioritizing APOL3. In the current study, we use reanalysis of population genetics datasets to resolve the haplotype contexts of all protein-altering APOL1 variants, uncovering previously unrecognized variant–haplotype couplings. We further characterize distinct cellular physiological properties among APOL1 splice isoforms, stressing the importance of isoform vB and what can be learned from isoform vC. Finally, a native interaction, and its interface, between APOL1 and APOL3 is reported, and shown to be differentially modulated by G1 and G2. We contend that continuing studies integrating these three interrelated domains will substantially advance mechanistic insights into APOL1 variant-driven renal injury, and leverage the findings to provide a more cohesive framework to guide future research.
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spelling doaj-art-e16abfe3c3fa460f8488f1d8ddc4344e2025-08-20T02:35:54ZengMDPI AGCells2073-44092025-07-011413101110.3390/cells14131011Apolipoprotein L1 (APOL1): Consideration of Molecular Evolution, Interaction with APOL3, and Impact of Splice Isoforms Advances Understanding of Cellular and Molecular Mechanisms of Cell InjuryRazi Khalaila0Karl Skorecki1Department of Nephrology, Rambam Health Care Campus, Haifa 3109601, IsraelDepartment of Nephrology, Rambam Health Care Campus, Haifa 3109601, IsraelThe Apolipoprotein L1 (APOL1) innate immunity gene product represents the sole member of the APOL gene family in humans capable of secretion into circulation, thereby mediating the trypanolysis of <i>T. brucei brucei</i>. Gain-of-function variants of the APOL1 gene originated and spread among human population groups to extend APOL1’s protective capacity to include also serum-resistant subspecies, such as <i>T. brucei gambiense</i> (S342G known as APOL1-G1) and <i>T. brucei rhodesiense</i> (N388_Y389del known as APOL1-G2). The biochemical pathways underlying the lytic activity of these evolutionary favored mutations against bloodstream trypanosomes have been elucidated with remarkable precision. However, the intricate molecular mechanisms by which such variants confer an increased susceptibility to renal cellular injury and consequent kidney disease remain incompletely defined. In the absence of a consistent mechanistic explanation for differential kidney injury, we propose pursuing three interrelated avenues of investigation informed by prior epidemiological and mechanistic evidence linking them to APOL1’s cytotoxicity: (1) Molecular evolution of APOL1 haplotypes in human populations, (2) APOL1 splicing and consequent splice isoforms, (3) Interaction of APOL1 with other APOL gene family members, prioritizing APOL3. In the current study, we use reanalysis of population genetics datasets to resolve the haplotype contexts of all protein-altering APOL1 variants, uncovering previously unrecognized variant–haplotype couplings. We further characterize distinct cellular physiological properties among APOL1 splice isoforms, stressing the importance of isoform vB and what can be learned from isoform vC. Finally, a native interaction, and its interface, between APOL1 and APOL3 is reported, and shown to be differentially modulated by G1 and G2. We contend that continuing studies integrating these three interrelated domains will substantially advance mechanistic insights into APOL1 variant-driven renal injury, and leverage the findings to provide a more cohesive framework to guide future research.https://www.mdpi.com/2073-4409/14/13/1011trypanosomiasistrypanosome lytic factorAPOL1 risk variantsAPOL1 splice variantsAPOL3signal peptide
spellingShingle Razi Khalaila
Karl Skorecki
Apolipoprotein L1 (APOL1): Consideration of Molecular Evolution, Interaction with APOL3, and Impact of Splice Isoforms Advances Understanding of Cellular and Molecular Mechanisms of Cell Injury
Cells
trypanosomiasis
trypanosome lytic factor
APOL1 risk variants
APOL1 splice variants
APOL3
signal peptide
title Apolipoprotein L1 (APOL1): Consideration of Molecular Evolution, Interaction with APOL3, and Impact of Splice Isoforms Advances Understanding of Cellular and Molecular Mechanisms of Cell Injury
title_full Apolipoprotein L1 (APOL1): Consideration of Molecular Evolution, Interaction with APOL3, and Impact of Splice Isoforms Advances Understanding of Cellular and Molecular Mechanisms of Cell Injury
title_fullStr Apolipoprotein L1 (APOL1): Consideration of Molecular Evolution, Interaction with APOL3, and Impact of Splice Isoforms Advances Understanding of Cellular and Molecular Mechanisms of Cell Injury
title_full_unstemmed Apolipoprotein L1 (APOL1): Consideration of Molecular Evolution, Interaction with APOL3, and Impact of Splice Isoforms Advances Understanding of Cellular and Molecular Mechanisms of Cell Injury
title_short Apolipoprotein L1 (APOL1): Consideration of Molecular Evolution, Interaction with APOL3, and Impact of Splice Isoforms Advances Understanding of Cellular and Molecular Mechanisms of Cell Injury
title_sort apolipoprotein l1 apol1 consideration of molecular evolution interaction with apol3 and impact of splice isoforms advances understanding of cellular and molecular mechanisms of cell injury
topic trypanosomiasis
trypanosome lytic factor
APOL1 risk variants
APOL1 splice variants
APOL3
signal peptide
url https://www.mdpi.com/2073-4409/14/13/1011
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AT karlskorecki apolipoproteinl1apol1considerationofmolecularevolutioninteractionwithapol3andimpactofspliceisoformsadvancesunderstandingofcellularandmolecularmechanismsofcellinjury