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Enrico Cabib

Bio: Enrico Cabib is an academic researcher from National Institutes of Health. The author has contributed to research in topics: Chitin & Chitin synthase. The author has an hindex of 60, co-authored 103 publications receiving 10246 citations. Previous affiliations of Enrico Cabib include Spanish National Research Council.


Papers
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Journal ArticleDOI
TL;DR: It is concluded that the latter polysaccharide has a central role in the organization of the yeast cell wall and the possible mechanism of synthesis and physiological significance of the cross-links is discussed.

607 citations

Journal ArticleDOI
TL;DR: Genetic evidence indicated that a mutant lacking all three chitin synthases was inviable; this was confirmed by constructing a triple mutant rescued by a plasmid carrying a CHS2 gene under control of a GAL1 promoter.
Abstract: The morphology of three Saccharomyces cerevisiae strains, all lacking chitin synthase 1 (Chs1) and two of them deficient in either Chs3 (calR1 mutation) or Chs2 was observed by light and electron microscopy. Cells deficient in Chs2 showed clumpy growth and aberrant shape and size. Their septa were very thick; the primary septum was absent. Staining with WGA-gold complexes revealed a diffuse distribution of chitin in the septum, whereas chitin was normally located at the neck between mother cell and bud and in the wall of mother cells. Strains deficient in Chs3 exhibited minor abnormalities in budding pattern and shape. Their septa were thin and trilaminar. Staining for chitin revealed a thin line of the polysaccharide along the primary septum; no chitin was present elsewhere in the wall. Therefore, Chs2 is specific for primary septum formation, whereas Chs3 is responsible for chitin in the ring at bud emergence and in the cell wall. Chs3 is also required for chitin synthesized in the presence of alpha-pheromone or deposited in the cell wall of cdc mutants at nonpermissive temperature, and for chitosan in spore walls. Genetic evidence indicated that a mutant lacking all three chitin synthases was inviable; this was confirmed by constructing a triple mutant rescued by a plasmid carrying a CHS2 gene under control of a GAL1 promoter. Transfer of the mutant from galactose to glucose resulted in cell division arrest followed by cell death. We conclude that some chitin synthesis is essential for viability of yeast cells.

448 citations

Journal ArticleDOI
TL;DR: Crystalline barium glucose g-phosphate was obtained from the Sigma Chemical Company, St. Louis, and intestinal phosphatase from Armour and Company, Chicago and the phosphat enzyme was dialyzed overnight against cold distilled water before use.

418 citations

Journal ArticleDOI
TL;DR: This paper presents a meta-analysis of cell wall synthesis after Cytokinesis and discusses the role of cdc genes, chitin, and other factors related to cell cycle events.
Abstract: PERSPECTIVES AND SUMMARY ....... ... . ... ....... . . . ........ ........ ... .. ..... .. ..... . .. 764 YEAST CELL WALL .. .. ..... .. ...... .... . .. ..... . . ... ....... ... ....... ........ ...... . ... ....... .. . ... 765 Chemistry 765 Structure ..... 767 CELL WALL AND SEPTUM FORMATION DURING THE YEAST CELL CyCLE 770 CELLULAR ASPECTS OF CELL WALL BIOSyNTHESIS 771 Initiation of Cell Wall Synthesis at Bud Emergence ........ . ..... ......... . .... ... .. . 771 Cell Wall Synthesis During Bud Enlargement ....... 773 Regulation of synthesis 773 Localization of synthesis 773 Insertion of new cell wall 774 Function of cdc genes 774 Septum Formation... ... ........ ...... ........ . . . . . ....... . . . .. ... ... 775 Relationship to other cell cycle events 775 Chitin synthesis .. .... ....... .. ...... . . ... . . ... . ..... .... . . ....... .... . ..... ..... ... ........ .. ....... ..... .. ... . 776 Cell Wall Synthesis after Cytokinesis ........ 776 Remarks 777

377 citations

Journal ArticleDOI
TL;DR: Radioactive chitin, prepared by acetylation of chitosan with tritiated acetic anhydride, was used as substrate in a rapid and extremely sensitive assay for chitInase, a result that cannot be attributed to an artifact of the method, to inhibition by product, or to instability of the enzyme.

341 citations


Cited by
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Journal ArticleDOI
23 Jan 1998-Science
TL;DR: Members of the Rho family of small guanosine triphosphatases have emerged as key regulators of the actin cytoskeleton, and through their interaction with multiple target proteins, they ensure coordinated control of other cellular activities such as gene transcription and adhesion.
Abstract: The actin cytoskeleton mediates a variety of essential biological functions in all eukaryotic cells. In addition to providing a structural framework around which cell shape and polarity are defined, its dynamic properties provide the driving force for cells to move and to divide. Understanding the biochemical mechanisms that control the organization of actin is thus a major goal of contemporary cell biology, with implications for health and disease. Members of the Rho family of small guanosine triphosphatases have emerged as key regulators of the actin cytoskeleton, and furthermore, through their interaction with multiple target proteins, they ensure coordinated control of other cellular activities such as gene transcription and adhesion.

5,969 citations

Journal ArticleDOI
TL;DR: In this review, functions of small G proteins and their modes of activation and action are described.
Abstract: Small GTP-binding proteins (G proteins) exist in eukaryotes from yeast to human and constitute a superfamily consisting of more than 100 members. This superfamily is structurally classified into at least five families: the Ras, Rho, Rab, Sar1/Arf, and Ran families. They regulate a wide variety of cell functions as biological timers (biotimers) that initiate and terminate specific cell functions and determine the periods of time for the continuation of the specific cell functions. They furthermore play key roles in not only temporal but also spatial determination of specific cell functions. The Ras family regulates gene expression, the Rho family regulates cytoskeletal reorganization and gene expression, the Rab and Sar1/Arf families regulate vesicle trafficking, and the Ran family regulates nucleocytoplasmic transport and microtubule organization. Many upstream regulators and downstream effectors of small G proteins have been isolated, and their modes of activation and action have gradually been elucidated. Cascades and cross-talks of small G proteins have also been clarified. In this review, functions of small G proteins and their modes of activation and action are described.

2,520 citations

Journal ArticleDOI
TL;DR: The Rho GTPases form a subgroup of the Ras superfamily of 20- to 30-kD GTP-binding proteins that have been shown to regulate a wide spectrum of cellular functions, and some of the more recent exciting findings hinting at novel, unanticipated functions of the RhoGTPases are summarized.
Abstract: The Rho GTPases form a subgroup of the Ras superfamily of 20- to 30-kD GTP-binding proteins that have been shown to regulate a wide spectrum of cellular functions. These proteins are ubiquitously expressed across the species, from yeast to man. The mammalian Rho-like GTPases comprise at least 10 distinct proteins: RhoA, B, C, D, and E; Rac1 and 2; RacE; Cdc42Hs, and TC10. A comparison of the amino acid sequences of the Rho proteins from various species has revealed that they are conserved in primary structure and are 50%–55% homologous to each other. Like all members of the Ras superfamily, the Rho GTPases function as molecular switches, cycling between an inactive GDP-bound state and an active GTP-bound state. Until recently, members of the Rho subfamily were believed to be involved primarily in the regulation of cytoskeletal organization in response to extracellular growth factors. However, research from a number of laboratories over the past few years has revealed that the Rho GTPases play crucial roles in diverse cellular events such as membrane trafficking, transcriptional regulation, cell growth control, and development. Consequently, a major challenge has been to unravel the underlying molecular mechanisms by which the Rho GTPases mediate these various activities. Many targets of the Rho GTPases have now been identified and further characterization of some of them has provided major insights toward our understanding of Rho GTPase function at the molecular level. This review aims to summarize the general established principles about the Rho GTPases and some of the more recent exciting findings, hinting at novel, unanticipated functions of the Rho GTPases.

2,429 citations

Journal ArticleDOI
TL;DR: The proteoglycan superfamily now contains more than 30 full-time molecules that fulfill a variety of biological functions and additional roles, derived from studies of mutant animals, indicate that certain proteoglycans are essential to life whereas others might be redundant.
Abstract: The proteoglycan superfamily now contains more than 30 full-time molecules that fulfill a variety of biological functions. Proteoglycans act as tissue organizers, influence cell growth and the maturation of specialized tissues, play a role as biological filters and modulate growth-factor activities, regulate collagen fibrillogenesis and skin tensile strength, affect tumor cell growth and invasion, and influence corneal transparency and neurite outgrowth. Additional roles, derived from studies of mutant animals, indicate that certain proteoglycans are essential to life whereas others might be redundant. The review focuses on the most recent genetic and molecular biological studies of the matrix proteoglycans, broadly defined as proteoglycans secreted into the pericellular matrix. Special emphasis is placed on the molecular organization of the protein core, the utilization of protein modules, the gene structure and transcriptional control, and the functional roles of the various proteoglycans. When possible, proteoglycans have been grouped into distinct gene families and subfamilies offering a simplified nomenclature based on their protein core design. The structure-function relationship of some paradigmatic proteoglycans is discussed in depth and novel aspects of their biology are examined.

1,650 citations