The plant ER-Golgi interface: a highly structured and dynamic membrane complex.
ABSTRACT As compared with other eukaryotic cells, plants have developed an endoplasmic reticulum (ER)-Golgi interface with very specific structural characteristics. ER to Golgi and Golgi to ER transport appear not to be dependent on the cytoskeleton, and ER export sites have been found closely associated with Golgi bodies to constitute entire mobile units. However, the molecular machinery involved in membrane trafficking seems to be relatively conserved among eukaryotes. Therefore, a challenge for plant scientists is to determine how these molecular machineries work in a different structural and dynamic organization. This review will focus on some aspects of membrane dynamics that involve coat proteins, SNAREs (soluble N-ethylmaleimide-sensitive factor attachment receptor proteins), lipids, and lipid-interacting proteins.
- Functional Plant Biology - FUNCT PLANT BIOL. 01/2009; 36(3).
- [Show abstract] [Hide abstract]
ABSTRACT: We discuss the quadric wavefront aberration of a fractional Talbot imaging ray which distorts the phase-type image of a binary amplitude grating with a small value of the opening ratio. When the opening ratio is equal to 1/2 or 1/3, the imaging rays are shown to have no quadric wavefront aberrations. For the opening ratios of 1/4 and 1/5, two different types of quadric wavefront aberrations are responsible for the three-level phase images. If the opening ratio gets to 1/6, we find that three different types of quadric wavefront aberrations distort the fractional Talbot image. The quadric wavefront aberration formulated here may be used in evaluating the phase-type image of a binary amplitude grating with an arbitrary value of the opening ratio.Optik - International Journal for Light and Electron Optics 01/2012; · 0.77 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: In the present study we employ FIB/SEM tomography for analyzing 3-D architecture of dictyosomes and formation of multivesicular bodies (MVB) in high pressure frozen and cryo-substituted interphase cells of the green algal model system Micrasterias denticulata. The ability of FIB/SEM of milling very thin 'slices' (5-10nm), viewing the block face and of capturing cytoplasmic volumes of several hundred μm(3) provides new insight into the close spatial connection of the ER-Golgi machinery in an algal cell particularly in z-direction, complementary to informations obtained by TEM serial sectioning or electron tomography. Our FIB/SEM series and 3-D reconstructions show that interphase dictyosomes of Micrasterias are not only closely associated to an ER system at their cis-side which is common in various plant cells, but are surrounded by a huge "trans-ER" sheath leading to an almost completely enwrapping of dictyosomes by the ER. This is particularly interesting as the presence of a trans-dictyosomal ER system is well known from mammalian secretory cells but not from cells of higher plants to which the alga Micrasterias is closely related. In contrast to findings in plant storage tissue indicating that MVBs originate from the trans-Golgi network or its derivatives our investigations show that MVBs in Micrasterias are in direct spatial contact with both, trans-Golgi cisternae and the trans-ER sheath which provides evidence that both endomembrane compartments are involved in their formation.Journal of Structural Biology 10/2013; · 3.37 Impact Factor