Randall Division of Cell and Molecular Biophysics

About: Randall Division of Cell and Molecular Biophysics is a based out in . It is known for research contribution in the topics: Actin cytoskeleton & Skeletal muscle. The organization has 576 authors who have published 1229 publications receiving 78279 citations.

GSATools: analysis of allosteric communication and functional local motions using a structural alphabet

Abstract: Motivation: GSATools is a free software package to analyze conformational ensembles and to detect functional motions in proteins by means of a structural alphabet. The software integrates with the widely used GROMACS simulation package and can generate a range of graphical outputs. Three applications can be supported: (i) investigation of the conformational variability of local structures; (ii) detection of allosteric communication; and (iii) identification of local regions that are critical for global functional motions. These analyses provide insights into the dynamics of proteins and allow for targeted design of functional mutants in theoretical and experimental studies. Availability: The C source code of the GSATools, along with a set of pre-compiled binaries, is freely available under GNU General Public License from http://mathbio.nimr.mrc.ac.uk/wiki/GSATools.

Defective skeletal muscle growth in lamin A/C-deficient mice is rescued by loss of Lap2α

Abstract: Mutations in lamin A/C result in a range of tissue-specific disorders collectively called laminopathies Of these, Emery-Dreifuss and Limb-Girdle muscular dystrophy 1B mainly affect striated muscle A useful model for understanding both laminopathies and lamin A/C function is the Lmna(-/-) mouse We found that skeletal muscle growth and muscle satellite (stem) cell proliferation were both reduced in Lmna(-/-) mice Lamins A and C associate with lamina-associated polypeptide 2 alpha (Lap2α) and the retinoblastoma gene product, pRb, to regulate cell cycle exit We found Lap2α to be upregulated in Lmna(-/-) myoblasts (MBs) To specifically test the contribution of elevated Lap2α to the phenotype of Lmna(-/-) mice, we generated Lmna(-/-)Lap2α(-/-) mice Lifespan and body mass were increased in Lmna(-/-)Lap2α(-/-) mice compared with Lmna(-/-) Importantly, the satellite cell proliferation defect was rescued, resulting in improved myogenesis Lmna(-/-) MBs also exhibited increased levels of Smad2/3, which were abnormally distributed in the cell and failed to respond to TGFβ1 stimulation as in control cells However, using SIS3 to inhibit signaling via Smad3 reduced cell death and augmented MB fusion Together, our results show that perturbed Lap2α/pRb and Smad2/3 signaling are important regulatory pathways mediating defective muscle growth in Lmna(-/-) mice, and that inhibition of either pathway alone or in combination can ameliorate this deleterious phenotype

The light chains of kinesin-1 are autoinhibited

Abstract: The light chains (KLCs) of the microtubule motor kinesin-1 bind cargoes and regulate its activity. Through their tetratricopeptide repeat domain (KLC(TPR)), they can recognize short linear peptide motifs found in many cargo proteins characterized by a central tryptophan flanked by aspartic/glutamic acid residues (W-acidic). Using a fluorescence resonance energy transfer biosensor in combination with X-ray crystallographic, biochemical, and biophysical approaches, we describe how an intramolecular interaction between the KLC2(TPR) domain and a conserved peptide motif within an unstructured region of the molecule, partly occludes the W-acidic binding site on the TPR domain. Cargo binding displaces this interaction, effecting a global conformational change in KLCs resulting in a more extended conformation. Thus, like the motor-bearing kinesin heavy chains, KLCs exist in a dynamic conformational state that is regulated by self-interaction and cargo binding. We propose a model by which, via this molecular switch, W-acidic cargo binding regulates the activity of the holoenzyme.