Paul Sabatier University

About: Paul Sabatier University is a education organization based out in Toulouse, France. It is known for research contribution in the topics: Population & Catalysis. The organization has 15431 authors who have published 23386 publications receiving 858364 citations.

OPA1 alternate splicing uncouples an evolutionary conserved function in mitochondrial fusion from a vertebrate restricted function in apoptosis

Abstract: In most eucaryote cells, release of apoptotic proteins from mitochondria involves fission of the mitochondrial network and drastic remodelling of the cristae structures. The intramitochondrial dynamin OPA1, as a potential central actor of these processes, exists as eight isoforms resulting from the alternate splicing combinations of exons (Ex) 4, 4b and 5b, which functions remain undetermined. Here, we show that Ex4 that is conserved throughout evolution confers functions to OPA1 involved in the maintenance of the DeltaPsi(m) and in the fusion of the mitochondrial network. Conversely, Ex4b and Ex5b, which are vertebrate specific, define a function involved in cytochrome c release, an apoptotic process also restricted to vertebrates. The drastic changes of OPA1 variant abundance in different organs suggest that nuclear splicing can control mitochondrial dynamic fate and susceptibility to apoptosis and pathologies.

Solution of Shannon's problem on the monotonicity of entropy

Abstract: It is shown that if X1, X2, . . . are independent and identically distributed square-integrable random variables then the entropy of the normalized sum Ent (X1+ · · · + Xn over √n) is an increasing function of n. This resolves an old problem which goes back to [6, 7, 5]. The result also has a version for non-identically distributed random variables or random vectors.