Malcolm Saul Steinberg (June 1, 1930 - February 7, 2012) was an American

biologist A biologist is a scientist who conducts research in biology. Biologists are interested in studying life on Earth, whether it is an individual Cell (biology), cell, a multicellular organism, or a Community (ecology), community of Biological inter ...

who proposed the

differential adhesion hypothesis Differential adhesion hypothesis (DAH) is a hypothesis that explains cellular movement during morphogenesis with thermodynamic principles. In DAH tissues are treated as liquids consisting of mobile cells whose varying degrees of surface adhesion ca ...

as a mechanism explaining cell sorting during

embryogenesis An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm ...

and

cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...

. Steinberg proposed that when cells form distinct tissues, specific cell-cell adhesion between cells from the same tissue can drive the separation. He further proposed that a difference in level of

cell adhesion molecules Cell adhesion molecules (CAMs) are a subset of cell surface proteins that are involved in the binding of cells with other cells or with the extracellular matrix (ECM), in a process called cell adhesion. In essence, CAMs help cells stick to each ...

expression between two cell types was sufficient to drive the separation. He confirmed these predictions in a model system in which adhesion between cells of a cultured line of mouse cells was controlled by genetic expression levels of

cadherin Cadherins (named for "calcium-dependent adhesion") are a type of cell adhesion molecule (CAM) that is important in the formation of adherens junctions to allow cells to adhere to each other . Cadherins are a class of type-1 transmembrane proteins, ...

. Steinberg pioneered work in characterizing the physical properties of cells and tissues. He proposed that cell-cell

adhesion Adhesion is the tendency of dissimilar particles or surfaces to cling to one another ( cohesion refers to the tendency of similar or identical particles/surfaces to cling to one another). The forces that cause adhesion and cohesion can be ...

drives tissue rounding up and, comparing tissues to liquids, he proposed that tissues have a

surface tension Surface tension is the tendency of liquid surfaces at rest to shrink into the minimum surface area possible. Surface tension is what allows objects with a higher density than water such as razor blades and insects (e.g. water striders) to f ...

. To measure tissue surface tension, he participated in building a compression device for rounded cell aggregates, and in sessile droplet experiments in which aggregates of cells were centrifuged at 37 degrees until their shapes reached equilibrium. Later experiments led him to conclude that differential adhesion, and an adhesion gradient, guide the salamander pronephric duct to the cloaca during embryonic development. Steinberg completed his BS at Amherst College in 1952, his PhD in zoology at the University of Minnesota in 1956, was a professor of biology at Johns Hopkins University from 1958 to 1966, and transferred to Princeton University in 1966, becoming professor emeritus in 2005.

References

American biologists Princeton University faculty University of Minnesota College of Biological Sciences alumni Amherst College alumni Johns Hopkins University faculty {{US-biologist-stub