When water temperatures change, the molecular motors of cephalopods do
too

Date:
June 8, 2023
Source:
University of California - San Diego
Summary:
Working with live squid hatchlings, scientists find the animals
can tune their proteome on the fly in response to changes in ocean
temperature via the unique process of RNA recoding. The findings
inspire new questions about basic protein function.


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FULL STORY ========================================================================== Cephalopods are a large family of marine animals that includes octopuses, cuttlefish and squid. They live in every ocean, from warm, shallow
tropical waters to near-freezing, abyssal depths. More remarkably,
report two scientists at University of California San Diego in a new
study, at least some cephalopods possess the ability to recode protein
motors within cells to adapt "on the fly" to different water temperatures.

Writing in the June 8, 2023 edition of Cell, first author Kavita
J. Rangan, PhD, a postdoctoral researcher in the lab of senior author
Samara L. Reck- Peterson, PhD, a professor in the departments of Cellular
and Molecular Medicine at UC San Diego School of Medicine and Cell
and Developmental Biology at UC San Diego and an Investigator of the
Howard Hughes Medical Institute, describe how opalescent inshore squid (Doryteuthis opalescens) employ RNA recoding to change amino acids at
the protein level, improving the function of molecular motors that carry
out diverse functions within cells in colder waters.

RNA recoding allows organisms to edit genetic information from the genomic blueprint to create new proteins. The process is rare in humans but is
common in soft-bodied cephalopods, such as D. opalescens, which makes
seasonal spawning migrations along the coast of San Diego.

"Cephalopods like D. opalescens are remarkable for their large nervous
systems, body innovations and complex behaviors" said Rangan, "and
their extensive use of RNA recoding has raised many questions about
how this process might be involved in responding to environmental cues
like temperature." In the new study, Rangan and Reck-Peterson looked
at changes to a pair of proteins in squid cells that serve as molecular
motors transporting a variety of intracellular cargoes along cellular
highways called microtubules.

Specifically, the researchers focused on molecular motor proteins called kinesin and dynein, both of which are fundamental to transportation
within all cells, including neurons. In humans, mutations in both motors
are linked to neurodegenerative diseases.

Working with live squid hatchlings at Scripps Institution of Oceanography, Rangan found that recoding of kinesin increased in animals as they
experienced colder ocean water temperatures. Rangan then recreated recoded kinesin proteins using recombinant DNA technology and biochemistry. She
then measured the movement of single motor molecules using advanced
light microscopy and found that the recoded kinesin motors functioned
better at cold temperatures.

"The work suggests that squid can tune their proteome (an organism's
entire complement of proteins) on the fly in response to changes in ocean temperature," said Reck-Peterson. "One can speculate that this allows
these marine ectotherms -- animals that depend on external sources of body
heat -- to survive and thrive in a broad range of ocean temperatures."
The scientists also found that RNA recoding varied across tissues,
generating new kinesin variants with distinct movement properties.

"This work supports the idea that recoding in cephalopods is important
for dynamically tuning protein function to support physiological needs and acclimate to changing environmental conditions" said Reck-Peterson. "These animals are taking a completely unique approach to adapting to their surroundings." Rangan said the findings also suggest the squid "editome"
may be a valuable resource for highlighting regions of molecules that
are amenable to plasticity or change. She is currently developing a
database that includes the entire squid editome across different ocean temperatures.

"In highly conserved proteins, like kinesin and dynein, cephalopod
recoding sites can point to overlooked residues of functional
significance, said Rangan, "and this has broader implications for
understanding basic protein function as well as for engineering proteins
with specific functions. Cephalopods may be able to show us where to
look and what changes to make."
* RELATED_TOPICS
o Plants_&_Animals
# Molecular_Biology # Cell_Biology # Biotechnology #
Genetics
o Earth_&_Climate
# Climate # Environmental_Awareness # Oceanography # Water
* RELATED_TERMS
o Protein_structure o Giant_squid o Colossal_Squid o Protein
o Housefly o RNA o Protein_folding o DNA

========================================================================== Story Source: Materials provided by
University_of_California_-_San_Diego. Original written by Scott
LaFee. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Kavita J. Rangan, Samara L. Reck-Peterson. RNA recoding in
cephalopods
tailors microtubule motor protein function. Cell, 2023; 186 (12):
2531 DOI: 10.1016/j.cell.2023.04.032 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2023/06/230608121028.htm

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