SEARCHOTHERophthalmology, cataract surgery

other·ophthalmology, cataract surgery, preclinical research, biomedical research·PMC10057792

Lens-specific βA3/A1-conditional knockout mice: Phenotypic characteristics and calpain activation causing protein degradation and insolubilization

PLOS ONE · 4 authors, 4 centres

AI SUMMARY

FIDELITY 100%

This summary was generated by AI from a single paper. It has not been reviewed by a clinician and is not clinical advice. Verify against the source before acting on it.

AGENT 01 · STRUCTURED SUMMARY

TRACE TO SOURCE

“

TL;DR

Lens-specific conditional knockout of βA3/A1-crystallin in mice caused congenital nuclear cataract at birth, associated with activation of calpain-3 that degraded and insolubilized lens structural proteins including β-tubulin, αA-crystallin, and phakinin.

Full summary

910 CHARS

Researchers generated a lens-specific βA3/A1-crystallin conditional knockout (βA3/A1ckO) mouse model to investigate functions of βA3/A1-crystallin in the lens beyond its structural role. βA3/A1ckO mice exhibited congenital nuclear cataract at birth and truncation of lens proteins. Mass spectrometric analysis of insoluble pellets from two centrifugation steps revealed that most truncated fragments with M_r < 20 kDa were derived from β-tubulin, with some from phakinin, αA-crystallin, and calpain-3. In vitro calcium treatment of wild-type lens homogenate activated calpain-3, which degraded calpain-3, αA-crystallin, and β-tubulin and caused insolubilization of these proteins. The results suggest that calpain-3 activation proteolyzes β-tubulin, disrupting microtubular structure and causing proteolysis of other lens proteins, whose insolubilization contributes to congenital nuclear cataract development.

STUDY TYPE

other

SPECIALTY

ophthalmology

SUMMARISED BY

AI pipeline

FIDELITY CHECK

100% · A

ORIGINAL PAPER

PMC10057792

Lens-specific βA3/A1-conditional knockout mice: Phenotypic characteristics and calpain activation causing protein degradation and insolubilization

PLOS ONE

READ THE FULL PAPER

ABSTRACT

βA3/A1-crystallin is a lens structural protein that plays an important role in maintaining lens transparency via interactions with other crystallins. While the function of βA3/A1-crystallin in the retina is well studied, its functions in the lens, other than as a structural protein, remain unclear. In the current study, we generated the lens-specific βA3/A1-crystallin conditional knockout mouse (named βA3/A1ckO) and explored phenotypic changes and the function of the crystallin in the lens. The βA3/A1ckO mice showed congenital cataract at birth and exhibited truncation of lens proteins. Several truncated protein fragments were recovered as a pellet during a low-speed centrifugation (800 rpm, 70 x g) followed by a relatively higher speed centrifugation (5000 rpm, 2744 x g). Mass spectrometric analysis of pellets recovered following the two centrifugations showed that among the fragments with M r < 20 kDa, the majority of these were from β-tubulin, and some from phakinin, αA-crystallin, and calpain-3. Further, we observed that in vitro activation of calpain-3 by calcium treatment of the wild-type-lens homogenate resulted in the degradation of calpain-3, αA-crystallin and β-tubulin and insolubilization of these proteins. Based on these results, it was concluded that the activation of calpain 3 resulted in proteolysis of β-tubulin, which disrupted cellular microtubular structure, and caused proteolysis of other lens proteins (αA-crystallin and phakinin). These proteolyzed protein fragments become insoluble, and together with the disruption of microtubular structure, and could be the causative factors in the development of congenital nuclear cataract in βA3/A1cKO mice.

CITATION EXPORT

Roy Joseph, Michael L. Robinson, Laura Lambert et al.. Lens-specific βA3/A1-conditional knockout mice: Phenotypic characteristics and calpain activation causing protein degradation and insolubilization. PLOS ONE. (2023). https://doi.org/10.1371/journal.pone.0281386

AUTHORS

4 · 4 CENTRES

Roy Joseph, Michael L. Robinson, Laura Lambert, Om P. Srivastava

1 Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, Alabama, United states of America
2 Department of Biology, Miami University, Oxford, Ohio, United states of America
3 Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
Tsinghua University School of Life Sciences, CHINA

EDITOR / REVIEWER

Yong-Bin Yan