Chen EB et al. (1998) Trends Genet "Understanding cell migration guidance: lessons from sex myoblast migration in C. elegans."

Chen EB, Stern MJ

[Trends Genet, 1998]

Studies of sex myoblast (SM) migration in the nematode Caenorhabditis elegans have shown that multiple guidance mechanisms cooperate to ensure the accurate and reproducible targeting of the SMs. Many issues arise in the analysis of SM migration, including the action of multiple guidance mechanisms, redundant sources of guidance information, the multiple uses of molecular components, and whether factors affect cell fate determination events or the guidance mechanisms themselves. These issues are common to many cell migration events and make the analysis of SM migration instructive to our general understanding of how cell migrations are controlled.

Walker JE et al. (1993) J Bioenerg Biomembr "The mitochondrial transport protein superfamily."

Runswick MJ, Walker JE

[J Bioenerg Biomembr, 1993]

The ADP/ATP, phosphate, and oxoglutarate/malate carrier proteins found in the inner membranes of mitochondria, and the uncoupling protein from mitochondria in mammalian brown adipose tissue, belong to the same protein superfamily. Established members of this superfamily have polypeptide chains approximately 300 amino acids long that consist of three tandem related sequences of about 100 amino acids. The tandem repeats from the different proteins are interrelated, and probably have similar secondary structures. The common features of this superfamily are also present in nine proteins of unknown functions characterized by DNA sequencing in various species, most notably in Caenorhabditis elegans and Saccharomyces cerevisiae. The high level expression in Escherichia coli of the bovine oxoglutarate/malate carrier, and the reconstitution of active carrier from the expressed protein, offers encouragement that the identity of superfamily members of known sequence but unknown function may be uncovered by a similar route.

Hutagalung AH et al. (2002) J Cell Sci "The UCS family of myosin chaperones."

Landsverk ML, Hutagalung AH, Price MG, Epstein HF

[J Cell Sci, 2002]

The canonical UCS (UNC-45/Crol/She4p) protein, Caenorhabditis elegans UNC-45, was one of the earliest molecules to be shown genetically to be necessary for sarcomere assembly. Genetic analyses of homologues in several fungal species indicate that the conserved UCS domain functionally interacts with conventional type II and unconventional type V myosins. In C. elegans and other invertebrate species, UNC-45 and its orthologues interact with both sarcomeric and non-sarcomeric myosins whereas, in vertebrates, there are two UNC-45 isoforms: a general cell (GC) and a striated muscle (SM) isoform. Although the mechanism of action of UCS proteins is unknown, recent biochemical studies suggest that they may act as molecular chaperones that facilitate the folding and/or maturation of myosin.

Jones TA et al. (2009) RNA Biol "A survey of nematode SmY RNAs."

Marz M, Eddy SR, Stadler PF, Jones TA, Otto W

[RNA Biol, 2009]

SmY RNAs are a family of approximately 70-90 nt small nuclear RNAs found in nematodes. In C. elegans, SmY RNAs copurify in a small ribonucleoprotein (snRNP) complex related to the SL1 and SL2 snRNPs that are involved in nematode mRNA trans-splicing. Here we describe a comprehensive computational analysis of SmY RNA homologs found in the currently available genome sequences. We identify homologs in all sequenced nematode genomes in class Chromadorea. We are unable to identify homologs in a more distantly related nematode species, Trichinella spiralis (class: Dorylaimia), and in representatives of non-nematode phyla that use trans-splicing. Using comparative RNA sequence analysis, we infer a conserved consensus SmY RNA secondary structure consisting of two stems flanking a consensus Sm protein binding site. A representative seed alignment of the SmY RNA family, annotated with the inferred consensus secondary structure, has been deposited with the Rfam RNA families database.

Mori K (2003) Traffic "Frame switch splicing and regulated intramembrane proteolysis: key words to understand the unfolded protein response."

Mori K

[Traffic, 2003]

Proteins must be correctly folded and assembled to fulfill their functions as assigned by genetic code. All living cells have developed systems to counteract protein unfolding or misfolding. A typical example of such a homeostatic response is triggered when unfolded proteins are accumulated in the endoplasmic reticulum. Eukaryotic cells cope with endoplasmic reticulum stress by attenuating translation, generally to decrease the burden on the folding machinery, as well as by inducing transcription of endoplasmic reticulum-localized molecular chaperones and folding enzymes to augment folding capacity. These translational and transcriptional controls are collectively termed the unfolded protein response. The unfolded protein response is unique in that the molecular mechanisms it uses to transmit signals from the endoplasmic reticulum lumen to the nucleus are completely different from those used for signaling from the plasma membrane. Frame switch splicing (a term newly proposed here) and regulated intramembrane proteolysis (proposed by Brown et al., Cell 2000; 100: 391-398) employed by the unfolded protein response represent novel ways to activate a signaling molecule post-transcriptionally and post-translationally, respectively. They are critically involved in various cellular regulation pathways ranging from bacterial extracytoplasmic stress response to differentiation of mature B cells into antibody-secreting plasma cells. Further, mammalian cells take advantage of differential properties between the two mechanisms to determine the fate of proteins unfolded or misfolded in the endoplasmic reticulum. This review focuses on the transcriptional control that occurs during the unfolded protein response in various species.