Physiological and Pathophysiological Insights of Nav1.4 and Nav1.5 Comparison.

Mutations in Nav1.4 and Nav1.5 α-subunits have been associated with muscular and cardiac channelopathies, respectively.

Dynamitin affects cell-surface expression of voltage-gated sodium channel Nav1.5.

The major cardiac voltage-gated sodium channel Nav1.5 associates with proteins that regulate its biosynthesis, localization, activity and degradation. Identification of partner proteins is crucial for a better understanding of the channel regulation.

IKs response to protein kinase A-dependent KCNQ1 phosphorylation requires direct interaction with microtubules.

Aims: KCNQ1 (alias KvLQT1 or Kv7.1) and KCNE1 (alias IsK or minK) co-assemble to form the voltage-activated K(+) channel responsible for I(Ks)-a major repolarizing current in the human heart-and their dysfunction promotes cardiac arrhythmias. The channel is a component of larger macromolecular complexes containing known and undefined regulatory proteins.

Mutations in the gene encoding filamin A as a cause for familial cardiac valvular dystrophy.

Background: Myxomatous dystrophy of the cardiac valves affects approximately 3% of the population and remains one of the most common indications for valvular surgery. Familial inheritance has been demonstrated with autosomal and X-linked transmission, but no specific molecular abnormalities have been documented in isolated nonsyndromic forms. We have investigated the genetic causes of X-linked myxomatous valvular dystrophy (XMVD) previously mapped to chromosome Xq28.

14-3-3 is a regulator of the cardiac voltage-gated sodium channel Nav1.5.

The voltage-sensitive Na(+) channel Na(v)1.5 plays a crucial role in generating and propagating the cardiac action potential and its dysfunction promotes cardiac arrhythmias. The channel takes part into a large molecular complex containing regulatory proteins.

Changes in the Activity of the Maturation-Promoting Factor Are Correlated with Those of a Major Cyclic AMP and Calcium-Independent Protein Kinase During the First Mitotic Cell Cycles in the Early Starfish Embryo: (cell cycle/maturation-promoting factor/protein kinase/protein synthesis/starfish).

Many studies suggest that MPF activation depends on protein phosphorylation or that MPF is itself a protein kinase. In the present report, cyclic variations of MPF activity have been correlated in vivo with changes in the extent of protein phosphorylation or in vitro with changes of a major protein kinase during the first cell cycles of fertilized starfish eggs. This cycling protein kinase neither requires cAMP nor Ca .

One Millimeter large Oocytes as a Tool to Study Hormonal Control of Meiotic Maturation in Starfish: Role of the Nucleus in Hormone-stimulated Phosphorylation of Cytoplasmic Proteins: (nucleus/maturation-promoting factor/protein phosphorylation).

Single nuclei (germinal vesicles) manually isolated from large oocytes of the starfish Echinaster sepositus, as well as the complementary anucleated oocytes, were used to investigate the early changes of protein phosphorylation which occur from 1-MeAde addition to germinal vesicle breakdown (GVBD). Stimulation of protein phosphorylation was already evident in the nucleus shortly after 1-MeAde addition (18 min, thus about 0.40x the time required for GVBD), although it began first in the cytoplasm.