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A holin/peptidoglycan hydrolase‐dependent protein secretion system
Author(s) -
Palmer Tracy,
Finney Alexander J.,
Saha Chayan Kumar,
Atkinson Gemma C.,
Sargent Frank
Publication year - 2021
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.14599
Subject(s) - secretion , biology , peptidoglycan , periplasmic space , secretory pathway , secretory protein , lysin , microbiology and biotechnology , lytic cycle , bacterial cell structure , inner membrane , biochemistry , cell wall , bacteria , cell , golgi apparatus , escherichia coli , bacteriophage , genetics , gene , virus , mitochondrion
Gram‐negative bacteria have evolved numerous pathways to secrete proteins across their complex cell envelopes. Here, we describe a protein secretion system that uses a holin membrane protein in tandem with a cell wall‐editing enzyme to mediate the secretion of substrate proteins from the periplasm to the cell exterior. The identity of the cell wall‐editing enzymes involved was found to vary across biological systems. For instance, the chitinase secretion pathway of Serratia marcescens uses an endopeptidase to facilitate secretion, whereas the secretion of Typhoid toxin in Salmonella enterica serovar Typhi relies on a muramidase. Various families of holins are also predicted to be involved. Genomic analysis indicates that this pathway is conserved and implicated in the secretion of hydrolytic enzymes and toxins for a range of bacteria. The pairing of holins from different families with various types of peptidoglycan hydrolases suggests that this secretion pathway evolved multiple times. We suggest that the complementary bodies of evidence presented is sufficient to propose that the pathway be named the Type 10 Secretion System (TXSS).