Immunolocalisation of protein phosphatase inhibitor-1 in the cerebral cortex of the rat, cat and ferret

Löwenstein, Pedro R.; Shering, A.F.; MacDougall, Lindsay K.; Cohen, Patricia T.W.

doi:10.1016/0006-8993(95)00091-4

Cited by 11 publications

(8 citation statements)

References 29 publications

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“…6, left panel). The I-1 band, corresponding to the dog heart, was below 30 kDa, whereas the rat I-1 appeared higher than 30 kDa, in agreement with their apparent molecular mass (25)(26)(27). In parallel, the antibody for the non-phosphorylated Thr-75 recognized this form in the same samples (Fig.…”

Section: Figure 3 Pkc-␣ Time Course Of In Vitro Phosphorylation Of Rsupporting

confidence: 61%

Identification of a Novel Phosphorylation Site in Protein Phosphatase Inhibitor-1 as a Negative Regulator of Cardiac Function

Rodríguez

Mitton

Waggoner

et al. 2006

Journal of Biological Chemistry

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Human and experimental heart failure is characterized by increases in type-1 protein phosphatase activity, which may be partially attributed to inactivation of its endogenous regulator, protein phosphatase inhibitor-1. Inhibitor-1 represents a nodal integrator of two major second messenger pathways, adenosine 3,5-cyclic monophosphate (cAMP) and calcium, which mediate its phosphorylation at threonine 35 and serine 67, respectively. Here, using recombinant inhibitor-1 wild-type and mutated proteins, we identified a novel phosphorylation site in inhibitor-1, threonine 75. This phosphoamino acid was phosphorylated in vitro by protein kinase C␣ independently and to the same extent as serine 67, the previous protein kinase C␣-identified site. Generation of specific antibodies for the phosphorylated and dephosphorylated threonine 75 revealed that this site is phosphorylated in rat and dog hearts. Adenoviral-mediated expression of the constitutively phosphorylated threonine 75 inhibitor-1 in isolated myocytes was associated with specific stimulation of type-1 protein phosphatase activity and marked inhibition of the sarcoplasmic calcium pump affinity for calcium, resulting in depressed contractility. Thus, phosphorylation of inhibitor-1 at threonine 75 represents a new mechanism of cardiac contractility regulation, partially through the alteration of sarcoplasmic reticulum calcium transport activity.A fine-tuned regulation of protein kinase and protein phosphatase activities is essential in the control of the phosphorylation state of various key phosphoprotein substrates, which modulate glycogen metabolism, protein synthesis, cell division, neuronal signaling, and muscle contraction (1-3). A cross-talk between the second messenger cAMP-dependent protein kinase (PKA) 4 and the type-1 protein phosphatase (PP1) occurs at the level of an endogenous phosphoprotein, inhibitor-1 (I-1), allowing amplification of the cAMP signaling cascade. Inhibitor-1 was first identified in rabbit skeletal muscle (4), but it is widely expressed in mammalian tissues and highly conserved across species (5). This thermostable protein, upon phosphorylation by PKA at Thr-35, potently inhibits PP1, enhancing cAMP-mediated protein phosphorylation (6 -9). In cardiac muscle, the regulation of PP1 by I-1 has been shown to play a major role in both basal contractility (2, 10), as well as in the heart response to ␤-adrenergic stimulation (11, 12). The positive inotropic effect of the ␤-agonist, isoproterenol, is accompanied by I-1 phosphorylation, resulting in inhibition of PP1 activity (13). This decrease in PP1 augments the cAMP-stimulating effects in enhancing cardiac contractility by preventing the dephosphorylation of important proteins involved in regulating the contractile state of the heart. Intriguingly, a constitutively activated form of I-1 (T35D; AA1-65) enhanced cardiac function and the heart response to ␤-adrenergic agonists, and protected the heart from developing hypertrophy induced by pressure overload (10). Furthermore, acute adenovira...

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Section: Figure 3 Pkc-␣ Time Course Of In Vitro Phosphorylation Of Rsupporting

confidence: 61%

Identification of a Novel Phosphorylation Site in Protein Phosphatase Inhibitor-1 as a Negative Regulator of Cardiac Function

Rodríguez

Mitton

Waggoner

et al. 2006

Journal of Biological Chemistry

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“…1C a band of f 29 kDa (rat) or f 26 kDa (rabbit, human) was detected by the I-1 antibody, but not by its preimmune serum. The species-dependent difference in size of I-1 and the apparent molecular mass are in accord published data [6,8,9]. To get an estimate of the absolute level of I-1 in human heart tissue, a dilution of recombinant rat I-1 (6.25 -25 ng) was probed with the FB 70 antiserum in parallel with a dilution of TCA-extract from a non-failing heart (3.5 -14 Ag; Fig.…”

Section: Detection and Quantitation Of I-1 Protein In Immunoblotsmentioning

confidence: 84%

Decreased protein and phosphorylation level of the protein phosphatase inhibitor-1 in failing human hearts

El‐Armouche

Pamminger

Ditz

et al. 2004

Cardiovascular Research

127

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“…In the striatum, both DARPP-32 and I-1 are found in dendrites and spines of medium spiny projection neurons (Hemmings and Greengard, 1986; Gustafson et al, 1991; Hemmings et al, 1992; Ouimet et al, 1992), but neither has been observed in cholinergic- or neuropeptide Y-containing interneurons of the striatum (Anderson and Reiner, 1991; Gustafson et al, 1991; Reiner et al, 1998). In the cortex, both DARPP-32 and I-1 have been identified in spiny pyramidal projection neurons, but also in local circuit interneurons (Berger et al, 1990; Gustafson et al, 1991; Lowenstein et al, 1995; Trantham-Davidson et al, 2008). Interestingly, the sole electron microscopic (EM) examination of either protein in the cortex suggested that I-1 is almost exclusively localized to dendrites (Lowenstein et al, 1995).…”

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confidence: 99%

“…In the cortex, both DARPP-32 and I-1 have been identified in spiny pyramidal projection neurons, but also in local circuit interneurons (Berger et al, 1990; Gustafson et al, 1991; Lowenstein et al, 1995; Trantham-Davidson et al, 2008). Interestingly, the sole electron microscopic (EM) examination of either protein in the cortex suggested that I-1 is almost exclusively localized to dendrites (Lowenstein et al, 1995). Furthermore, in the striatum DARPP-32 is extensively co-localized with the D 1 dopamine receptor in medium spiny neurons (Ouimet et al, 1984; Walaas and Greengard, 1984; Bateup et al, 2008; Bertran-Gonzalez et al, 2008), but confocal microscopic examination of interneuron dendrites which demonstrated electrophysiological responses to D1R agents in mouse frontal cortex did not show DARPP-32 label (Trantham-Davidson et al, 2008).…”

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confidence: 99%

Localization of dopamine- and cAMP-regulated phosphoprotein-32 and inhibitor-1 in area 9 of Macaca mulatta prefrontal cortex

Glausier

Maddox²,

Hemmings

et al. 2010

Neuroscience

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The actions of dopamine D1 family receptors (D1R) depend upon a signal transduction cascade that modulates the phosphorylation state of important effector proteins, such as glutamate receptors and ion channels. This is accomplished both through activation of protein kinase A (PKA) and the inhibition of protein phosphatase-1 (PP1). Inhibition of PP1 occurs through PKA-mediated phosphorylation of DARPP-32 or the related protein inhibitor-1 (I-1), and the availability of DARPP-32 is essential to the functional outcome of D1R activation in the basal ganglia. While D1R activation is critical for prefrontal cortex (PFC) function, especially working memory, the functional role played by DARPP-32 or I-1 is less clear. In order to examine this more thoroughly, we have utilized immunoelectron microscopy to quantitatively determine the localization of DARPP-32 and I-1 in the neuropil of the rhesus monkey PFC. Both were distributed widely in the different components of the neuropil, but were enriched in dendritic shafts. I-1 label was more frequently identified in axon terminals than was DARPP-32, and DARPP-32 label was more frequently identified in glia than was I-1. We also quantified the extent to which these proteins were found in dendritic spines. DARPP-32 and I-1 were present in small subpopulations of dendritic spines, (4.4 and 7.7% and respectively), which were substantially smaller than observed for D1R in our previous studies (20%). Double-label experiments did not find evidence for colocalization of D1R and DARPP-32 or I-1 in spines or terminals. Thus, at the least, not all prefrontal spines which contain D1R also contain I-1 or DARPP-32, suggesting important differences in D1R signaling in the PFC compared to the striatum. Corresponding author: E. Chris Muly, Yerkes National Primate Research Center, 954 Gatewood Rd. NE, Atlanta, GA 30329, telephone (404) 727-9603, facsimile (404) 727-3278, emuly@emory.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Author ManuscriptNeuroscience. Author manuscript; available in PMC 2011 May 5. The functional effects of activating D 1 or D 5 , the dopamine D1 family receptors (D1R), depend on a complex signal transduction pathway. The basic scheme of D1R signal transduction involves the coupling of D1R to G αs to activate adenylyl cyclase (AC) and produce cyclic AMP (cAMP) which, in turn, activates protein kinase A (PKA). PKA phosphorylates a variety of substrate proteins, and it is the altered phosphorylation of key signaling proteins that accounts for much of the effects of D1R stimulation. The actions of PK...

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Immunolocalisation of protein phosphatase inhibitor-1 in the cerebral cortex of the rat, cat and ferret

Cited by 11 publications

References 29 publications

Identification of a Novel Phosphorylation Site in Protein Phosphatase Inhibitor-1 as a Negative Regulator of Cardiac Function

Identification of a Novel Phosphorylation Site in Protein Phosphatase Inhibitor-1 as a Negative Regulator of Cardiac Function

Decreased protein and phosphorylation level of the protein phosphatase inhibitor-1 in failing human hearts

Localization of dopamine- and cAMP-regulated phosphoprotein-32 and inhibitor-1 in area 9 of Macaca mulatta prefrontal cortex

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