Proteoglycans and Orchids: the Work of Vincent Hascall
Year: 2007
Type: article
Abstract: Aggregation of Cartilage Proteoglycans: III. CHARACTERISTICS OF THE PROTEINS ISOLATED FROM TRYPSIN DIGESTS OF AGGREGATESJournal of Biological ChemistryVol. 249Issue 13PreviewA protein-hyaluronic acid complex was isolated from Sepharose 2B chromatography of a sequential chondroitinase plus trypsin digest of a proteoglycan aggregate preparation from bovine nasal cartilage. Two proteins were subsequently isolated from this complex by Sephadex G-200 chromatography with 4 m guanidine hydrochloride as the eluent. Sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that the two proteins had molecular weights of about 90,000 and 45,000 and that treatment with β-mercaptoethanol did not decrease their sizes. Full-Text PDF Open Access Proteinpolysaccharide Complex from Bovine Nasal Cartilage. A Comparison of Low and High Shear Extraction Procedures (Sajdera, S. W., and Hascall, V. C. (1969) J. Biol. Chem. 244, 77–87) Proteinpolysaccharide Complex from Bovine Nasal Cartilage. The Function of Glycoprotein in the Formation of Aggregates (Hascall, V. C., and Sajdera, S. W. (1969) J. Biol. Chem. 244, 2384–2396) Aggregation of Cartilage Proteoglycans. III. Characteristics of the Proteins Isolated from Trypsin Digests of Aggregates (Heinegård, D., and Hascall, V. C. (1974) J. Biol. Chem. 249, 4250–4256) Vincent C. Hascall, Jr. was born in Burwell, Nebraska in 1940. He attended the California Institute of Technology and earned a B.S. in 1962. After graduating he enrolled at Rockefeller University, where he earned his Ph.D. in 1969. While at Rockefeller, Hascall met Alan Kapuler who had won a Westinghouse Prize in high school for using a new method for meristem cultures on an orchid species. As a result Kapuler was taken to Bogota, Colombia to learn how specimens were collected and preserved. “Alan suggested that we take a summer and go collecting orchids in Central America and Colombia,” recalls Hascall. “Rockefeller University agreed to let us do it, and Alan's parents gave us an old Renault Dauphin 2-cylinder car, and we drove from Manhattan down through Central America to Panama, put the car on a boat and went on to Colombia. In Colombia, on the Pacific Ocean side, we explored a region that had large, moss ridden trees alongside a road. In the moss of one of the trees, I noticed some small orange dots. They turned out to be what is likely the smallest orchid in the world. The flower is the size of the head of a pin. It was a new species.” Kapuler and Hascall named the orchid Platystele acutilingua (1Hascall V.C. Kapuler A.M. Collecting along a transect: from the rain forest to the Andes in Choco, Colombia.American Orchid Society Bulletin. 1966; 35: 540-544Google Scholar). (see Fig. 1). The genus Platystele was known, but the species name, acutilingua, meaning sharp tongue, was their contribution. However, for his thesis research, Hascall chose to focus on cartilage rather than orchids. “I ended up in the basement of one of the Rockefeller research buildings next to the East River in a small lab with Stan Sajdera, a fellow graduate student,” recalls Hascall. “We taught as lab techs in a summer biochemistry lab course headed by Dominic Dziewiatkowski, who had cartilage experiments going. Both of us then continued to work with cartilage for our Ph.D. work.” Dziewiatkowski accepted a position at the University of Michigan before Hascall and Sajdera finished their research at Rockefeller. The two students continued their research without Dziewiatkowski and were able to develop an extraction and purification procedure for proteoglycans on their own. This work is the subject of the first and second Journal of Biological Chemistry (JBC) Classics reprinted here. At the time this research was published, scientists were using high speed homogenization in low ionic strength salt solutions to extract proteinpolysaccharides (now called proteoglycans) from tissue. However, this method introduced shear artifacts and denatured and depolymerized the macromolecules. In a serendipitous experiment, Sajdera, who was exploring the effects of reducing agents and denaturants on the isolation and activity of the proteoglycans, used 4 m guanidine HCl as a control for the extraction of cartilage slices. To Hascall and Sajdera's surprise, almost all of the proteoglycans were released into the solution whereas the slices remained intact. In a series of follow-up experiments, they showed that this extraction method caused proteoglycan aggregates in the cartilage to dissociate, thereby allowing the proteoglycan monomer (now called aggrecan) to diffuse into the extraction solvent. This procedure, which they termed “the dissociative extraction method” for proteoglycans, is still used today. The Classic paper became the basis for Sajdera's Ph.D thesis. In the second Classic paper, Hascall and Sajdera showed that cartilage proteoglycans in the dissociative extracts reformed aggregates when dialyzed into lower, associative solvent concentrations (0.4 m guanidine HCl). They also showed that a protein they named the glycoprotein link protein was required for successful aggregation. This paper became the basis for Hascall's Ph.D. thesis. What Hascall and Sajdera did not know at the time, however, was that hyaluronan was present in the extracts and also required for aggregation. After receiving his Ph.D., Hascall joined the faculty of the University of Michigan as an assistant professor. A couple years later, in 1972, he met Dick Heinegård at a Gordon Conference. Heinegård invited Hascall to spend a year in his laboratory at the University of Lund in Sweden. Hascall accepted the offer and was off to Sweden the next year. When he arrived, he learned that Hardingham and Muir had just discovered that by adding small amounts of hyaluronan to a solution of proteoglycan monomer, they could induce the formation of proteoglycan aggregates (2Hardingham T.E. Muir H. The specific interaction of hyaluronic acid with cartilage proteoglycans.Biochim. Biophys. Acta. 1972; 279: 401-405Crossref PubMed Scopus (419) Google Scholar). Curious about this phenomenon, Heinegård and Hascall began their own series of investigations. The final JBC Classic paper reprinted here is the last in a series of three that the two scientists published (3Hascall V.C. Heinegård D. Aggregation of cartilage proteoglycans. I. The role of hyaluronic acid.J. Biol. Chem. 1974; 249: 4232-4241Abstract Full Text PDF PubMed Google Scholar, 4Hascall V.C. Heinegård D. Aggregation of cartilage proteoglycans. II. Oligosaccharide competitors of the proteoglycan-hyaluronic acid interaction.J. Biol. Chem. 1974; 249: 4242-4249Abstract Full Text PDF PubMed Google Scholar), which finally put all the pieces together to define the role of hyaluronan and the link protein in forming the cartilage proteoglycan (aggrecan) aggregates. By digesting aggregated proteoglycan with proteases, Heinegård and Hascall were able to show that two proteins were bound to hyaluronan. One protein was the link protein, and the other was derived from a domain of the core protein of aggrecan, now referred to as the G1 domain. These results led to a model for the proteoglycan aggregates in which the link protein and the G1 domain were bound to each other as well as to hyaluronan (see Fig. 2). After returning from Sweden, Hascall spent 2 more years at the University of Michigan as an associate professor. In 1975, he became Senior Staff Fellow in the Laboratory of Biochemistry at the National Institute of Dental Research, National Institutes of Health. He eventually became Chief of the Proteoglycan Chemistry Section in the Laboratory of Biochemistry at the National Institute of Dental Research, a position he held until he left the NIH in 1994 to join the Department of Biomedical Engineering at the Cleveland Clinic Foundation. From 2001 to 2005, Hascall was co-director of the Orthopaedic Research Center at the Cleveland Clinic. Today, he remains at the Cleveland Clinic and also holds a position as a professor in the Department of Biological Chemistry at Case Western Reserve University. In addition to his scientific research, Hascall is an Associate Editor for the Journal of Biological Chemistry, a position he has held since 1995. He also received the NIH Merit Award in 1979, was President of the Society for Complex Carbohydrates in 1987, and was awarded the Karl Meyer Award for Glycoconjugate Research from the Society for Complex Carbohydrates in 1992. 1Biographical information on Vincent Hascall was taken from Ref. 5Hascall V.C. Hyaluronan, a common thread.Glycoconj. J. 2000; 17: 607-616Crossref PubMed Scopus (21) Google Scholar. 1Biographical information on Vincent Hascall was taken from Ref. 5Hascall V.C. Hyaluronan, a common thread.Glycoconj. J. 2000; 17: 607-616Crossref PubMed Scopus (21) Google Scholar.
Source: Journal of Biological Chemistry
Language: English
Subfield: Cell Biology
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
OpenAlex ID: W1877554451