Plants possess a greater number of reticulon isoforms, with 21 having been identified in the commonly used model organism Arabidopsis thaliana.
C-terminal region of RTNs contains a highly conservative reticulon homology domain (RHD) while other parts of the protein may vary even within a single organism.
This reticulon subform is curiously absent in fish,[4] a taxon known for the heightened ability of its CNS to regenerate after injury.
[5] Reticulon proteins, which range from 200-1,200 amino acids, have been tracked in all eukaryotic organisms that have been examined.
Some examples of explored reticulon genomes of eukaryotes are in Homo sapiens, Mus musculus, Danio rerio, Drosophila melanogaster, Arabidopsis thaliana, and Saccharomyces cerevisiae.
Because of their absence from prokaryotes and close association with the endoplasmic reticulum (ER), it is proposed that reticulons have evolved with the eukaryotic endomembrane system.
[2] The first reticulon protein RTN1 was characterized as an antigen for neuroendocrine cells from a cDNA in neural tissue.
Reticulons have localized to the ER in the following organisms: yeast, Arabidopsis, Xenopus, Drosophila and mammals.
[2] Evidence shows that reticulons influence ER and Golgi-body trafficking in and out of the cell through plasma membrane-associated proteins.
In C. elegans, removing RTNL RET−1 and associated proteins interferes with the formation of the ER during mitosis.
Reticulons have been found to interact with proteins that are involved with vesicular formation and morphogenesis of the ER.
In one example, it was shown that increasing expression of RTN3 keeps transport of proteins from retrograding from the Golgi bodies to the ER.
[2] The longest isoform of RTN4 has been studied extensively to show that this protein (Nogo-A) was identified as an inhibitor of neurite outgrowth.
[2] Many studies in animals have found that inhibition of a NogoA interaction has promoted axon growth and recovery after a spinal cord injury.
In the most common mutated protein in hereditary spastic paraplegia, spastin, there was an interaction with both RTN1 and RTN3 through two-hybrid screening.
[2] Additionally, ALS could be predicted with increased expression of RTN4A in lower motor neuron syndromes.
[6] Scientists have inferred that reticulons have a role in assembling the nuclear envelope during cell division.
[7] Although there is not a direct interference, RTNLB1 and RTNLB2 interact with newly created FLS2 to facilitate transport to the plasma membrane.
Those members were expressed in tobacco leaf epidermal cells with an attached yellow fluorescent protein (YFP).
Fluorescence recovery after photobleaching (FRAP) analysis has shown that increased expression of RTNLB13 decreases the likeliness of proteins to be soluble in the ER lumen.
[9] To further examine that location of RTNS are the ER, the increased expression of RTNLB13 did not have an effect on the Golgi shape and secretion of a reporter protein.