Evolution of factors shaping the endoplasmic reticulum

Area of Science:

• Cell Biology
• Evolutionary Biology
• Genomics

Background:

• The endomembrane system, particularly the endoplasmic reticulum (ER), is vital for eukaryotic cell functions.
• The evolutionary origins and lineage-specific modifications of ER-associated proteins remain understudied.
• Understanding ER protein evolution sheds light on organelle structure and function.

Purpose of the Study:

• To investigate the evolutionary history of proteins crucial for maintaining ER structure and function.
• To identify conserved and lineage-specific ER-associated proteins through comparative genomics.
• To understand the diversification of ER maintenance mechanisms across eukaryotic lineages.

Main Methods:

• Comparative genomics analysis of experimentally characterized ER-associated proteins.
• Tracing the evolutionary conservation and loss of specific ER protein families.
• Identifying lineage-specific protein innovations in ER maintenance.

Main Results:

• Key ER structure proteins like reticulons, REEPs, and atlastins are highly conserved, predating the last eukaryotic common ancestor (LECA).
• Secondary losses of ER-associated proteins are observed in specific lineages, such as lunapark absence in Stramenopiles and Alveolata.
• Novel ER maintenance factors, including protrudin and CLIMP-63, are identified as lineage-specific innovations within Opisthokonta.

Conclusions:

• A significant portion of the ER-building and maintenance machinery predates the last eukaryotic common ancestor (LECA).
• Eukaryotes exhibit diverse evolutionary strategies for ER shape and function maintenance.
• Further experimental studies in various eukaryotes are expected to reveal novel ER maintenance mechanisms.