The Pex3–Inp1 complex tethers yeast peroxisomes to the plasma membrane

A subset of peroxisomes is retained at the mother cell cortex by the Pex3–Inp1 complex. We identify Inp1 as the first known plasma membrane–peroxisome (PM-PER) tether by demonstrating that Inp1 meets the predefined criteria that a contact site tether protein must adhere to. We show that Inp1 is present in the correct subcellular location to interact with both the plasma membrane and peroxisomal membrane and has the structural and functional capacity to be a PM-PER tether. Additionally, expression of artificial PM-PER tethers is sufficient to restore retention in inp1Δ cells. We show that Inp1 mediates peroxisome retention via an N-terminal domain that binds PI(4,5)P2 and a C-terminal Pex3-binding domain, forming a bridge between the peroxisomal membrane and the plasma membrane. We provide the first molecular characterization of the PM-PER tether and show it anchors peroxisomes at the mother cell cortex, suggesting a new model for peroxisome retention

Design criteria of neuron/electrode interface. The focused ion beam technology as an analytical method to investigate the effect of electrode surface morphology on neurocompatibility

"Neurocompatibility" is a broad definition which comprises aspects of biocompatibility, chemical and physical surface properties, and biostability of an artificial substrate interfaced with a neural tissue. The main issue coming from the analysis of the state of art of neuroprosthesis and neuron/electrode interfaces is the strong influence of electrode surface morphology on neurocompatibility. Enhanced functions of neurons have been observed on nano-structured materials. This paper proposes the use of focused ion beam (FIB) technology as high precision machining technique to modify the surface morphology of an interface material. By controlling the ion milling in three dimensions, the fabrication of a surface with any predefined morphology becomes possible with nanometric precision. In vitro tests on PC12 cells cultured on surfaces with different morphologies show that the surface morphology influences the cell adhesion. Experimental results suggest an enhancement of the interaction between cells and artificial surfaces at a specific scale (tens of nanometres) which is the typical scale of cellular interaction in the extra-cellular matrix (ECM) of living organisms