Contractile proteins isoforms in placental vessels

Cavaillé, Françoise; A, Kacemi; Mondon, Françoise; Fournier, Thierry; Ferrè, Francesca

doi:10.1016/s0143-4004(05)80484-9

Cited by 2 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is known that the final target of substances participating in fetoplacental blood flow regulation is the vessel musculature, through the activity of proteins of the contractile apparatus, particularly of smooth muscle type isoforms of actin and myosin heavy chain, previously found in high levels in placental vessels at the end of pregnancy [32]. However, the presence of non-negligible quantities of nonmuscle protein isoforms in stem villi vessels indicates some degree of immaturity as reported in embryonic vessels, which would be representative of a proliferating phenotype in which the IGF system would have a role [39].…”

Section: Discussionmentioning

confidence: 92%

Identification and Characterization of 125I-Insulin-Like Growth Factor-II Binding Sites on the Muscular Layer of Stem Villi Vessels of Human Term Placenta1

Rebourcet

Deborde

Ceuninck

et al. 1996

Biology of Reproduction

Self Cite

View full text Add to dashboard Cite

The primary function of the placenta is to ensure an optimal environment for fetal growth and development. In normal pregnancy, placental vascular tone regulation assures fetus well-being and normal development by maintaining adequate blood flow so as to ensure materno-fetal exchanges. In human placenta, synthesis of insulin-like growth factor (IGF)-II and specific binding sites have been previously characterized in the trophoblast; in contrast, no studies have dealt with this subject in the fetoplacental vascular system, particularly in stem villi vessels. We thus investigated whether membranes of the muscular layer of stem villi vessels contained 125I-IGF-II binding sites. Two complementary approaches were used: 125I-IGF-II binding and affinity cross-linking studies. 125I-IGF-II labeled, in a saturable and noncooperative manner, a single class of high-affinity binding sites characterized by a Kd of 1.24 +/- 0.26 nM (n = 6), a maximum binding capacity (Bmax) of 3.02 +/- 0.45 pmol/mg protein, and a Hill coefficient of 1.00 +/- 0.15. Competitors for 125I-IGF-II binding to membranes were in the order of potency IGF-II > IGF-I. Insulin was not a competitor. Affinity cross-linking of membranes with 125I-IGF-II, followed by SDS-PAGE and autoradiography, revealed two labeled bands: a protein complex of 250 kDa, which corresponds to the type II IGF receptor, and another of 135 kDa, corresponding to the type I IGF receptor. Only IGF-II could displace 125I-IGF-II binding from the major 250-kDa band, while 125I-IGF-II bound to the minor 135-kDa band was displaced by either IGF-I, IGF-II, or insulin. In conclusion, high levels of specific binding sites for 125I-IGF-II are present in the muscular layer of stem villi vessels, which are considered placenta resistance vessels. The involvement of both type I and type II IGF receptors in the growth-promoting action of IGF-II remains to be determined in the fetoplacental vascular system.

show abstract

Section: Discussionmentioning

confidence: 92%

Identification and Characterization of 125I-Insulin-Like Growth Factor-II Binding Sites on the Muscular Layer of Stem Villi Vessels of Human Term Placenta1

Rebourcet

Deborde

Ceuninck

et al. 1996

Biology of Reproduction

Self Cite

View full text Add to dashboard Cite

show abstract

“…PKCβ 2 became associated with actin filaments when activated [21], suggesting its involvement in the contractile process. It should be noted that feto‐placental vessels contain a large amount of α‐smooth muscle actin isoform [22]. The absence of PKCγ was expected, since this isoform is mainly found in the brain or brain‐derived tissues.…”

Section: Discussionmentioning

confidence: 97%

Regulation of protein kinase C in the muscular layer of human placental stem villi vessels

1998

View full text Add to dashboard Cite

Protein kinase C (PKC) activity in the muscular layer of stem villi vessels from the human term placenta was studied. Resting state PKC activity was distributed evenly between the cytosol and the particulate fractions. Upon stimulation by three different activators, phorbol 12-myristate 13-acetate, fluoride and endothelin-1, a translocation of PKC activity from the cytosolic to the particulate fraction was observed. The expression and distribution of PKC isoforms were then examined by Western blot analysis using specific antibodies to PKC isoforms. At least four PKC isoforms, PKCK K, PKCL L I , PKCL L P , PKCj j, and trace amounts of PKCO O were detected in both fractions. Their relative responses to the different agonists were examined by quantifying their subcellular redistribution. No significant differential activation of the four mainly expressed PKC isoforms were observed in response to stimulation with any of the stimuli. Moreover, our results show that endothelin-1 induced translocation/activation of PKC in this vascular smooth muscle.z 1998 Federation of European Biochemical Societies.

show abstract

Contractile proteins isoforms in placental vessels

Cited by 2 publications

References 0 publications

Identification and Characterization of 125I-Insulin-Like Growth Factor-II Binding Sites on the Muscular Layer of Stem Villi Vessels of Human Term Placenta1

Identification and Characterization of 125I-Insulin-Like Growth Factor-II Binding Sites on the Muscular Layer of Stem Villi Vessels of Human Term Placenta1

Regulation of protein kinase C in the muscular layer of human placental stem villi vessels

Contact Info

Product

Resources

About