scholarly journals Molecular basis of selective IgG2 deficiency. The mutated membrane-bound form of gamma2 heavy chain caused complete IGG2 deficiency in two Japanese siblings.

1998 ◽  
Vol 101 (3) ◽  
pp. 677-681 ◽  
Author(s):  
H Tashita ◽  
T Fukao ◽  
H Kaneko ◽  
T Teramoto ◽  
R Inoue ◽  
...  
Keyword(s):  
Heavy Chain ◽  
Molecular Basis ◽  
Igg2 Deficiency ◽  
Membrane Bound

scholarly journals Fate of the mutated IgG2 heavy chain: lack of expression of mutated membrane-bound IgG2 on the B cell surface in selective IgG2 deficiency

2001 ◽  
Vol 13 (2) ◽  
pp. 249-256 ◽  
Author(s):  
Tomoyoshi Terada ◽  
Hideo Kaneko ◽  
Toshiyuki Fukao ◽  
Hideaki Tashita ◽  
Ai Lian Li ◽  
...  
Keyword(s):  
Cell Surface ◽  
B Cell ◽  
Heavy Chain ◽  
Igg2 Deficiency ◽  
Membrane Bound

Molecular Basis of Dystrobrevin Interaction with Kinesin Heavy Chain: Structural Determinants of their Binding

2005 ◽  
Vol 354 (4) ◽  
pp. 872-882 ◽  
Author(s):  
Marina Ceccarini ◽  
Paola Torreri ◽  
Dario Giuseppe Lombardi ◽  
Gianfranco Macchia ◽  
Pompeo Macioce ◽  
...  
Keyword(s):  
Heavy Chain ◽  
Molecular Basis ◽  
Structural Determinants ◽  
Kinesin Heavy Chain

scholarly journals Plasma membrane association of Acanthamoeba myosin I.

1989 ◽  
Vol 109 (4) ◽  
pp. 1519-1528 ◽  
Author(s):  
H Miyata ◽  
B Bowers ◽  
E D Korn
Keyword(s):  
Plasma Membrane ◽  
Binding Site ◽  
Heavy Chain ◽  
Membrane Fraction ◽  
Plasma Membranes ◽  
Actin Binding ◽  
Plasma Membrane Fraction ◽  
Myosin I ◽  
Membrane Bound ◽  
Actin Binding Site

Myosin I accounted for approximately 2% of the protein of highly purified plasma membranes, which represents about a tenfold enrichment over its concentration in the total cell homogenate. This localization is consistent with immunofluorescence analysis of cells that shows myosin I at or near the plasma membrane as well as diffusely distributed in the cytoplasm with no apparent association with cytoplasmic organelles or vesicles identifiable at the level of light microscopy. Myosin II was not detected in the purified plasma membrane fraction. Although actin was present in about a tenfold molar excess relative to myosin I, several lines of evidence suggest that the principal linkage of myosin I with the plasma membrane is not through F-actin: (a) KI extracted much more actin than myosin I from the plasma membrane fraction; (b) higher ionic strength was required to solubilize the membrane-bound myosin I than to dissociate a complex of purified myosin I and F-actin; and (c) added purified myosin I bound to KI-extracted plasma membranes in a saturable manner with maximum binding four- to fivefold greater than the actin content and with much greater affinity than for pure F-actin (apparent KD of 30-50 nM vs. 10-40 microM in 0.1 M KCl plus 2 mM MgATP). Thus, neither the MgATP-sensitive actin-binding site in the NH2-terminal end of the myosin I heavy chain nor the MgATP-insensitive actin-binding site in the COOH-terminal end of the heavy chain appeared to be the principal mechanism of binding of myosin I to plasma membranes through F-actin. Furthermore, the MgATP-sensitive actin-binding site of membrane-bound myosin I was still available to bind added F-actin. However, the MgATP-insensitive actin-binding site appeared to be unable to bind added F-actin, suggesting that the membrane-binding site is near enough to this site to block sterically its interaction with actin.

Controlling the Pathway for Prothrombin Activation by Prothrombinase.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1695-1695
Author(s):  
Michael A. Bukys ◽  
Paul Y. Kim ◽  
Michael E. Nesheim ◽  
Michael Kalafatis
Keyword(s):  
Amino Acid ◽  
Heavy Chain ◽  
Factor Xa ◽  
Competitive Inhibitor ◽  
Amino Acid Region ◽  
Factor Va ◽  
Initial Cleavage ◽  
Membrane Bound ◽  
Prothrombin Activation ◽  
Thrombin Formation

Abstract Prothrombinase is the enzymatic complex responsible for timely thrombin formation. Activation of human prothrombin is the consequence of two cleavages at Arg271 and Arg320 in prothrombin by factor Xa. Membrane-bound factor Xa alone catalyzes prothrombin activation following initial cleavage at Arg271 and prethrombin 2 formation (pre2 pathway). Factor Va directs prothrombin activation by factor Xa through the meizothrombin pathway, characterized by initial cleavage at Arg320 (meizo pathway). We have previously shown that a pentapeptide encompassing amino acid sequence 695–699 from the COOH-terminus of the heavy chain of factor Va (Asp-Tyr-Asp-Tyr-Gln, DYDYQ) interacts with anion binding exosite I (ABE-I) of thrombin and inhibits prothrombin activation by prothrombinase. The peptide was found to be a competitive inhibitor of prothrombinase with respect to substrate. According to the mode of inhibition, we postulated that the peptide binds prothrombin in competition with the binding of the substrate to the enzyme, and inhibits prothrombinase activity by substrate depletion. This mode of DYDYQ inhibition of prothrombin activation by the factor Va-factor Xa complex is similar to that previously demonstrated for sulfated hirugen. To understand the mechanism of inhibition of thrombin formation by DYDYQ we have studied prothrombin activation by gel electrophoresis. Titration of plasma-derived prothrombin activation by fully assembled prothrombinase, with increasing concentrations of peptide, resulted in complete inhibition of the meizo pathway. However, thrombin formation still occurred through the pre2 pathway. Higher peptide concentrations were required to impair thrombin formation through the latter pathway. These data demonstrate that the peptide preferentially inhibits initial cleavage of prothrombin by prothrombinase at Arg320. These findings were corroborated by studying the kinetics of activation of recombinant mutant prothrombin molecules rMZ-II (R155A/R284A/R271A) and rP2-II (R155A/R284A/R320A) which can be only cleaved at Arg320 and Arg271 respectively. Cleavage of rMZ-II by prothrombinase was completely inhibited by low concentrations of DYDYQ while high concentrations of pentapeptide were required to inhibit cleavage of rP2-II. The pentapeptide also interfered with thrombin formation by membrane-bound factor Xa alone in the absence of factor Va. Nonetheless, while the rate for cleavage at Arg271 of plasma-derived prothrombin or rP2-II by membrane-bound factor Xa alone was significantly accelerated in the presence of DYDYQ, resulting in accumulation of prethrombin 2, the rate for cleavage at Arg320 of plasma-derived prothrombin or rMZ-II by membrane-bound factor Xa alone was only moderately affected by the pentapeptide. Our data demonstrate that a pentapeptide mimicking amino acids 695–699 of the heavy chain of factor Va has opposing effects on membrane-bound factor Xa for prothrombin activation, depending on the incorporation of factor Va in prothrombinase. In the presence of the cofactor the peptide inhibits the rate of thrombin generation by specifically interfering with initial cleavage of prothrombin at Arg320, while in the absence of factor Va the pentapeptide accelerates cleavage of prothrombin by factor Xa at Arg271. Thus, the amino acid region spatially surrounding proexosite I in prothrombin most likely has two interactive sites for the components of prothrombinase, a factor Va interactive site and a factor Xa binding site.

Translocations involving the immunoglobulin heavy-chain locus are possible early genetic events in patients with primary systemic amyloidosis

Blood ◽  
2001 ◽  
Vol 98 (7) ◽  
pp. 2266-2268 ◽  
Author(s):  
Suzanne R. Hayman ◽  
Richard J. Bailey ◽  
Syed M. Jalal ◽  
Gregory J. Ahmann ◽  
Angela Dispenzieri ◽  
...  
Keyword(s):  
Heavy Chain ◽  
Molecular Basis ◽  
Monoclonal Gammopathy ◽  
Immunoglobulin Heavy Chain ◽  
Systemic Amyloidosis ◽  
Igh Locus ◽  
Genetic Events ◽  
14Q32 Translocation ◽  
Undetermined Significance

Primary systemic amyloidosis (AL) is a plasma cell (PC) dyscrasia with clinical similarities to multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS), but its molecular basis is poorly understood. Translocations at the immunoglobulin heavy-chain (IgH) locus, 14q32, are likely early genetic events in both MM and MGUS and involve several nonrandom, recurrent, partner chromosomes such as 11q13, 16q23, and 4p16.3. Given the similarities between MM, MGUS, and AL, bone marrow clonal PCs were evaluated in 29 patients with AL using interphase fluorescence in situ hybridization (FISH) combined with immunofluorescence detection of the cytoplasmic light-chain (cIg-FISH) for the presence of 14q32 translocations and the t(11;14)(q13;q32). Of 29 patients studied, 21 (72.4%) showed results compatible with the presence of a 14q32 translocation, and 16 (76.2%) of those had translocation (11;14)(q13;q32) for an overall prevalence of the abnormality of 55%. IgH translocations are common in AL, especially the t(11;14)(q13;q32).

scholarly journals Four novel myosin heavy chain transcripts define a molecular basis for muscle fibre types inRanapipiens

1998 ◽  
Vol 508 (3) ◽  
pp. 667-680 ◽  
Author(s):  
Gordon J. Lutz ◽  
Denise B. Cuizon ◽  
Allen F. Ryan ◽  
Richard L. Lieber
Keyword(s):  
Myosin Heavy Chain ◽  
Muscle Fibre ◽  
Heavy Chain ◽  
Molecular Basis ◽  
Fibre Types ◽  
Muscle Fibre Types

scholarly journals Allelic exclusion in transgenic mice carrying mutant human IgM genes.

1988 ◽  
Vol 167 (6) ◽  
pp. 1969-1974 ◽  
Author(s):  
M C Nussenzweig ◽  
A C Shaw ◽  
E Sinn ◽  
J Campos-Torres ◽  
P Leder
Keyword(s):  
Transgenic Mice ◽  
Heavy Chain ◽  
Chain Gene ◽  
Allelic Exclusion ◽  
Heavy Chain Gene ◽  
F1 Hybrid ◽  
Membrane Bound ◽  
Ig Heavy Chain ◽  
Simultaneous Expression

Expression of the membrane-bound version of the human mu chain in transgenic mice results in the allelic exclusion of endogenous mouse Ig heavy chain genes (6). The secreted version of the human Ig transgene has no such effect. F1 hybrid animals that carry transgenes for both secreted and membrane-bound human mu chains produce both forms of the human heavy chain while strongly suppressing endogenous mouse mu expression. The simultaneous expression of the two rearranged transgenes in primary B cells suggests that allelic exclusion operates before the formation of a second functionally rearranged heavy chain gene in vivo.

scholarly journals The Molecular Basis of Cluster Formation by Membrane-Bound Lipidated Ras

2012 ◽  
Vol 102 (3) ◽  
pp. 259a
Author(s):  
Alemayehu A. Gorfe ◽  
Zhenlong Li ◽  
Lorant Janosi
Keyword(s):  
Molecular Basis ◽  
Cluster Formation ◽  
Membrane Bound
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