Biology

Evolutionary diversification of the HAP2 membrane insertion motifs to drive gamete fusion across eukaryotes

by Juliette Fedry, Jennifer Forcina, Pierre Legrand, Gérard Péhau-Arnaudet, Ahmed Haouz, Mark Johnson, Felix A. Rey, Thomas Krey

HAPLESS2 (HAP2) is a broadly conserved, gamete-expressed transmembrane protein that was shown recently to be structurally homologous to viral class II fusion proteins, which initiate fusion with host cells via insertion of fusion loops into the host membrane. However, the functional conformation of the HAP2 fusion loops has remained unknown, as the reported X-ray structure of Chlamydomonas reinhardtii HAP2 lacked this critical region. Here, we report a structure-guided alignment that reveals diversification of the proposed HAP2 fusion loops. Representative crystal structures show that in flowering plants, HAP2 has a single prominent fusion loop projecting an amphipathic helix at its apex, while in trypanosomes, three small nonpolar loops of HAP2 are poised to interact with the target membrane. A detailed structure-function analysis of the Arabidopsis HAP2 amphipathic fusion helix defines key residues that are essential for membrane insertion and for gamete fusion. Our study suggests that HAP2 may have evolved multiple modes of membrane insertion to accommodate the diversity of membrane environments it has encountered during eukaryotic evolution.

Source link

Related posts

Exceptionally Long Lived Humans Exhibit Slower Epigenetic Aging, Measured by DNA Methlyation Clocks

Newsemia

A Few Snags Near Ketchum and Stanley

Newsemia

People Remain Hopeful that Something Useful can be Accomplished with Minoxidil

Newsemia

This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish. Accept Read More

Privacy & Cookies Policy

COVID-19

COVID-19 (Coronavirus) is a new illness that is having a major effect on all businesses globally LIVE COVID-19 STATISTICS FOR World