Electron Microscope Observations on the Endoplasmic Reticulum in the Human Fetal Adrenal

Ross, Michael H.; Pappas, George D.; Lanman, Jonathan T.; Lind, John

doi:10.1083/jcb.4.5.659

Cited by 54 publications

(19 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…So far, our and other laboratories have agreed that the catalytic activity of HMGR is not required for ER remodeling Profant et al, 1999). However, the requirement of the catalytic activity for the phospholipid effects we observed demands reevaluation of the role of the enzymatic activity in the full effects of HMGR, as would be expected to occur in the natural cases of ER remodeling caused by this enzyme, such as in adrenal cortical cells, or other professional sterol-synthesizing cells (Ross et al, 1958;Sisson and Fahrenbach, 1967;Black, 1972). Similarly, recent work from the Wright group has found a connection to HMGR enzyme activity in the cellular growth responses to elevated Hmg1p (Loertscher et al, 2006;Wright et al, 2003).…”

Section: Discussionmentioning

confidence: 76%

Genetic and Structural Analysis of Hmg2p-induced Endoplasmic Reticulum Remodeling inSaccharomyces cerevisiae

Federovitch

Jones

Tong

et al. 2008

MBoC

View full text Add to dashboard Cite

The endoplasmic reticulum (ER) is highly plastic, and increased expression of distinct single ER-resident membrane proteins, such as HMG-CoA reductase (HMGR), can induce a dramatic restructuring of ER membranes into highly organized arrays. Studies on the ER-remodeling behavior of the two yeast HMGR isozymes, Hmg1p and Hmg2p, suggest that they could be mechanistically distinct. We examined the features of Hmg2p required to generate its characteristic structures, and we found that the molecular requirements are similar to those of Hmg1p. However, the structures generated by Hmg1p and Hmg2p have distinct cell biological features determined by the transmembrane regions of the proteins. In parallel, we conducted a genetic screen to identify HER genes (required for Hmg2p-induced ER Remodeling), further confirming that the mechanisms of membrane reorganization by these two proteins are distinct because most of the HER genes were required for Hmg2p but not Hmg1p-induced ER remodeling. One of the HER genes identified was PSD1, which encodes the phospholipid biosynthetic enzyme phosphatidylserine decarboxylase. This direct connection to phospholipid biosynthesis prompted a more detailed examination of the effects of Hmg2p on phospholipid mutants and composition. Our analysis revealed that overexpression of Hmg2p caused significant and specific growth defects in nulls of the methylation pathway for phosphatidylcholine biosynthesis that includes the Psd1p enzyme. Furthermore, increased expression of Hmg2p altered the composition of cellular phospholipids in a manner that implied a role for PSD1. These phospholipid effects, unlike Hmg2p-induced ER remodeling, required the enzymatic activity of Hmg2p. Together, our results indicate that, although related, Hmg2p-and Hmg1p-induced ER remodeling are mechanistically distinct.

show abstract

Section: Discussionmentioning

confidence: 76%

Genetic and Structural Analysis of Hmg2p-induced Endoplasmic Reticulum Remodeling inSaccharomyces cerevisiae

Federovitch

Jones

Tong

et al. 2008

MBoC

View full text Add to dashboard Cite

show abstract

“…If the agranular reticulum is involved in the biosynthesis of androgens in the interstitial cells, one might expect to find a similar development of this organelle in other steroid-secreting organs, such as the adrenal cortex, corpus luteum, or theca interna of the Graafian follicle. This is indeed the case in human fetal adrenal cortical cells (38), in lutein cells of the mouse corpus luteum (45), and in ovarian interstitial cells in mice (26). However, in the majority of electron microscope studies of the adrenal cortex, the endoplasmic reticulum has been reported to be poorly developed, and to consist of individual vesicles (46,18).…”

Section: Figure 1~mentioning

confidence: 97%

The Normal Fine Structure of Opossum Testicular Interstitial Cells

Christensen

Fawcett

1961

The Journal of Cell Biology

249

View full text Add to dashboard Cite

The interstitial tissue of the opossum testis includes interstitial or Leydig cells, macrophages, and small cells which morphologically resemble mesenchymal cells. The latter are thought to give rise to mature interstitial cells. The most prominent feature of the interstitial cell cytoplasm is an exceedingly abundant agranular endoplasmic reticulum. This reticulum is generally in the form of a meshwork of interconnected tubules about 300 to 450 A in diameter, but occasionally it assumes the form of flattened, fenestrated cisternae resembling those of pancreatic acinar cells, except for the lack of ribonucleoprotein particles on the surface of the membranes. The interstitial cells vary considerably in their cytoplasmic density. The majority are quite light, but some appear extremely dense, and in addition usually have a more irregular cell surface, with numerous small pseudopodia. These differences may well reflect variations in physiological state. Cytoplasmic structures previously interpreted as "crystalloids" consist of long bundles of minute parallel tubules, each about 180 A in diameter, which seem to be local differentiations of the endoplasmic reticulum. The mitochondria are rod-shaped, and contain a moderately complex internal membrane structure, and also occasional large inclusions that are spherical and homogeneous. The prominent juxtanuclear Golgi complex contains closely packed flattened sacs and small vesicles. The results of the present study, coupled with biochemical evidence from other laboratories, make it seem highly probable that the agranular endoplasmic reticulum is involved in the synthesis of the steroid hormones produced by the interstitial cell. This finding therefore constitutes one of the first functions of the agranular reticulum for which there is good morphological and biochemical evidence.

show abstract

“…17), sometimes closely applied to them; and because the ending also contains dense mitochondria that have been damaged or otherwise modified, the identification and classification of the bodies is difficult. Ross et al (1958) reported finding a similar mass of fine tubular endoplasmie reticulum, also associated with lipid droplets, in the foetal zone of the steroid-producing human foetal adrenal; and they note that, according to Palade (1955), the smooth surfaced rather than the rough surfaced reticulum is found to predominate in cells active in lipid metabolism.…”

Section: Myotube Regionmentioning

confidence: 99%

The Fine Structure of Muscle Spindles in the Lumbrical Muscles of the Rat

Merrillees

1960

The Journal of Cell Biology

112

View full text Add to dashboard Cite

Lumbrical muscles of young rats were fixed with Os04 and embedded in methacrylate for electron microscopy. The spindle capsule was found to be continuous with and similar in structure to the sheath of Henle surrounding the nerves supplying the spindle. The capsule consists of several closely applied concentric cytoplasmic sheets. Each sheet is about 1,000 A thick and has no fenestrations. Many caveolae and vesicles in the cytoplasm suggest active transport through the sheets. The periaxial space fluid contains much solid material. It is suggested that the capsule and periaxial space regulate internal chemical environment.The interfibrillar structures are less evident in the polar regions of intrafusal fibres than in extrafusal fibres. Simple motor end-plates occur on the polar regions of intrafusal fibres. In the myotube region of the intrafusal fibre a peripheral zone of myofibrils surrounds a cytoplasmic core containing nuclei, mitochondria, Golgi bodies, reticulum, and a few lipid-like granules. Naked sensory endings lie on the myotube "in parallel" with the underlying myofilaments. Naked processes of the primary sensory ending deeply indent the muscle plasma membrane and the underlying wisps of myofilament in the nuclear bag region.The plasma membranes of sensory nerve ending and intrafusal muscle fibre are about 200 A apart.

show abstract

Electron Microscope Observations on the Endoplasmic Reticulum in the Human Fetal Adrenal

Cited by 54 publications

References 8 publications

Genetic and Structural Analysis of Hmg2p-induced Endoplasmic Reticulum Remodeling inSaccharomyces cerevisiae

Genetic and Structural Analysis of Hmg2p-induced Endoplasmic Reticulum Remodeling inSaccharomyces cerevisiae

The Normal Fine Structure of Opossum Testicular Interstitial Cells

The Fine Structure of Muscle Spindles in the Lumbrical Muscles of the Rat

Contact Info

Product

Resources

About