The secretory pathway in peptide hormone-producing cells

Contains fulltext : mmubn000001_234153458.pdf (publisher's version ) (Open Access)Promotor : G. Martens cum laude135 p

Mechanism and significance of P4 ATPase-catalyzed lipid transport: lessons from a Na+/K+-pump

Members of the P4 subfamily of P-type ATPases are believed to catalyze phospholipid transport across membrane bilayers, a process influencing a host of cellular functions. Atomic structures and functional analysis of P-type ATPases that pump small cations and metal ions revealed a transport mechanism that appears to be conserved throughout the family. A challenging problem is to understand how this mechanism is adapted in P4 ATPases to flip phospholipids. P4 ATPases form oligomeric complexes with members of the CDC50 protein family. While formation of these complexes is required for P4 ATPase export from the endoplasmic reticulum, little is known about the functional role of the CDC50 subunits. The Na+/K+-ATPase and closely-related H+/K+-ATPase are the only other P-type pumps that are oligomeric, comprising mandatory β-subunits that are strikingly reminiscent of CDC50 proteins. Besides serving a role in the functional maturation of the catalytic α-subunit, the β-subunit also contributes specifically to intrinsic transport properties of the Na+/K+ pump. As β-subunits and CDC50 proteins likely adopted similar structures to accomplish analogous tasks, current knowledge of the Na+/K+-ATPase provides a useful guide for understanding the inner workings of the P4 ATPase class of lipid pumps

Cell biology : A brake on lipid synthesis

Although sphingolipids are vital cellular components, the path to their production is paved with toxic intermediates. Orm proteins allow cells to form these lipids without killing themselves in the proces

Sensing membrane curvature

AbstractTransport vesicle formation and fusion are highly regulated processes that require the sequential assembly and disassembly of proteinacious membrane coats. Recent work suggests that one of the coat proteins senses the local changes in lipid packing that accompany membrane bending during vesiculation, and thus acts as a timer for coat disassembly once a complete vesicle is formed

The neuroendocrine proteins secretogranin II and III are regionally conserved and coordinately expressed with proopiomelanocortin in Xenopus intermediate pituitary

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Molecular Probing of the Secretory Pathway in Peptide Hormone-Producing Cells

Contains fulltext : 29537___.PDF (publisher's version ) (Open Access

Sphingolipid transport in eukaryotic cells

Sphingolipids constitute a sizeable fraction of the membrane lipids in all eukaryotes and are indispensable for eukaryotic life. First of all, the involvement of sphingolipids in organizing the lateral domain structure of membranes appears essential for processes like protein sorting and membrane signaling. In addition, recognition events between complex glycosphingolipids and glycoproteins are thought to be required for tissue differentiation in higher eukaryotes and for other specific cell interactions. Finally, upon certain stimuli like stress or receptor activation, sphingolipids give rise to a variety of second messengers with effects on cellular homeostasis. All sphingolipid actions are governed by their local concentration. The intricate control of their intracellular topology by the proteins responsible for their synthesis, hydrolysis and intracellular transport is the topic of this revie