Lewis G. Tilney is an American cell biologist and

professor emeritus ''Emeritus'' (; female: ''emerita'') is an adjective used to designate a retired chair, professor, pastor, bishop, pope, director, president, prime minister, rabbi, emperor, or other person who has been "permitted to retain as an honorary title ...

at the

University of Pennsylvania The University of Pennsylvania (also known as Penn or UPenn) is a private research university in Philadelphia. It is the fourth-oldest institution of higher education in the United States and is ranked among the highest-regarded universitie ...

. He received his

Ph.D. A Doctor of Philosophy (PhD, Ph.D., or DPhil; Latin: or ') is the most common degree at the highest academic level awarded following a course of study. PhDs are awarded for programs across the whole breadth of academic fields. Because it is a ...

from Cornell University Medical School in 1964. Tilney is known for studying the

cytoskeleton The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is compos ...

of animal cells, specifically how different components affect the cytoskeleton's overall properties.

Research and publications

Research interests

Tilney's research interests and primary research focus has been on the

of specific portions of animal cells. Through this research it was his goal to identify the cause behind certain properties of the cytoskeleton including length, distribution, and the location of each type of filament and

microtubule Microtubules are polymers of tubulin that form part of the cytoskeleton and provide structure and shape to eukaryotic cells. Microtubules can be as long as 50 micrometres, as wide as 23 to 27 nm and have an inner diameter between 11 an ...

. Some specific elements Tilney has investigated is the

microvilli Microvilli (singular: microvillus) are microscopic cellular membrane protrusions that increase the surface area for diffusion and minimize any increase in volume, and are involved in a wide variety of functions, including absorption, secretion, ...

intestinal The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans ...

epithelial cells Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellula ...

, the actin tail of '' Listeria'', the stereocilia of hair cells in the inner ear, and the bristles of ''

Drosophila ''Drosophila'' () is a genus of flies, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or (less frequently) pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species ...

''."Lewis Tilney". Nasonline.Org, 2020, http://www.nasonline.org/member-directory/m embers/3005869.html.

Drosophila

Tilney’s research in ''Drosophila'' focused on the

actin Actin is a family of globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in muscle fibrils. It is found in essentially all eukaryotic cells, where it may be present at a concentration of over ...

filaments. He observed the cross-linking of adjacent filaments and using forked proteins and

fascin Fascin is an actin bundling protein. Species and tissue distribution It is a 54-58 kilodalton monomeric actin filament bundling protein originally isolated from sea urchin egg but also found in ''Drosophila'' and vertebrates, including ...

investigated how the bundles formed. He observed that in mutants, the aggregation of bundles did not occur which resulted in significantly smaller bundle sizes compared to the wild type. From this, he performed experiments using and removing cross-linking agents forked proteins and

to investigate each cross-linkers role in properly forming actin bundles. From his work, he reached the conclusions that forked proteins are used early in the process to aggregate smaller bundles into large ones and they also help the bundles come together. Forked proteins also help fascin entry into the bundles which allows the bundles to cross-link and align properly. He conducted further experiments using antibodies specific to fascin and the forked proteins to show when they were present in actin formation. From this research, he was able to identify that fascin was present predominantly during bundle elongation whereas the forked proteins were present during bundle formation and consequently played a significant role in the shape and size of the actin bundles. Further, it was demonstrated the amount of actin

polymerization In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer, monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are ...

was also limited by the area where actin had the ability to adhere to connector material.

''Toxoplasma gondii''

Tilney also conducted research focused on ''

Toxoplasma gondii ''Toxoplasma gondii'' () is an obligate intracellular parasitic protozoan (specifically an apicomplexan) that causes toxoplasmosis. Found worldwide, ''T. gondii'' is capable of infecting virtually all warm-blooded animals, but felids, such as d ...

'' and how its invasive stages acted in an

-dependent fashion. To identify whether filaments form, Tilney induced actin polymerization on the

anterior Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

end of the parasite molecules using Jasplakinolide, an actin polymerization promoting and stabilizing molecule. Following the introduction of Jasplakinolide, it was observed that the actin-binding protein

myosin Myosins () are a superfamily of motor proteins best known for their roles in muscle contraction and in a wide range of other motility processes in eukaryotes. They are ATP-dependent and responsible for actin-based motility. The first myosin ...

connected to the newly formed polymer which confirmed its identity to be actin. This represented the first time that this actin polymerization had been observed in parasites. Later research went on to show how

protease A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes (increases reaction rate or "speeds up") proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the ...

inhibitors including

cysteine Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the formula . The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. When present as a deprotonated catalytic residue, sometime ...

and

serine Serine (symbol Ser or S) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated − form under biological conditions), a carboxyl group (which is in the deprotonated − form un ...

can modify the

post-translational modification Post-translational modification (PTM) is the covalent and generally enzymatic modification of proteins following protein biosynthesis. This process occurs in the endoplasmic reticulum and the golgi apparatus. Proteins are synthesized by ribosome ...

s in the processing of secretory proteins in the parasite.

Awards and honors

Tilney was elected into the

National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...

for cellular and developmental biology in 1998. He was elected alongside three other scientists in the field of

cellular biology Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living and ...

including Michael Levine,

Lelio Orci Lelio Orci (22 March 1937 – 22 October 2019) was an Italian scientist in the field of endocrinology and diabetes and emeritus professor in the Department of Morphology at the University of Geneva Medical School. Orci was born in 1937 in San Gi ...

, and Joan Ruderman. He was also awarded the

Guggenheim Fellowship Guggenheim Fellowships are grants that have been awarded annually since by the John Simon Guggenheim Memorial Foundation to those "who have demonstrated exceptional capacity for productive scholarship or exceptional creative ability in the ar ...

in 1975. This fellowship is awarded to those individuals who show excellent creativity in the sciences and produce scholarly work. It is awarded in the form of a grant that enables academic research."John Simon Guggenheim Foundation , About The Fellowship". Gf.Org, 2020, https://www.gf.org/about/fellowship/ .

References

{{DEFAULTSORT:Tilney, Lewis Cornell University alumni University of Pennsylvania faculty University of Pennsylvania Department of Biology faculty American cell biologists Year of birth missing (living people) Living people