scholarly journals A cytoplasmic protein kinase in Chlamydomonas couples engagement of ciliary receptors to rapid cellular responses

2021 ◽  
Author(s):  
Mayanka Awasthi ◽  
Peeyush Ranjan ◽  
Simon Kelterborn ◽  
Peter Hegemann ◽  
William J Snell
Keyword(s):  
Protein Kinase ◽  
Cell Fusion ◽  
Cellular Response ◽  
Fold Increase ◽  
Cellular Responses ◽  
Specific Protein ◽  
Cytoplasmic Protein ◽  
Extracellular Milieu ◽  
A Cell ◽  
Specific Protein Kinase

The principal function of the primary cilium is to convert cues from the extracellular milieu into changes in cyclic nucleotide concentration and cytoplasmic responses, but fundamental questions remain about the mechanisms of transmission of cilium-to-cytoplasm signals. During fertilization in Chlamydomonas reinhardtii, ciliary adhesion between plus and minus gametes triggers an immediate ~10-fold increase in cellular cAMP and activation for cell fusion. Here, we identify Gamete-Specific Protein Kinase (GSPK) as an essential link between cilary receptor engagement and gamete activation. The ciiary adhesion-induced increase in cAMP and cell fusion are severely impaired in gspk mutants but fusion is rescued by a cell-permeable form of cAMP, indicating that GSPK functions upstream of the cAMP increase. GSPK is cytoplasmic, and, remarkably, the entire cellular complement is phosphorylated in less than 60 seconds after ciliary contact. Thus, a cytoplasmic protein kinase rapidly converts a ciliary membrane cue into a global cellular response.

scholarly journals Suppression by wortmannin of platelet responses to stimuli due to inhibition of pleckstrin phosphorylation

1992 ◽  
Vol 285 (3) ◽  
pp. 745-751 ◽  
Author(s):  
Y Yatomi ◽  
O Hazeki ◽  
S Kume ◽  
M Ui
Keyword(s):  
Human Platelet ◽  
Cellular Responses ◽  
Specific Protein ◽  
Fungal Metabolite ◽  
Receptor Stimulation ◽  
Intact Cells ◽  
Kinase C ◽  
A Cell ◽  
Pkc Activation ◽  
Specific Protein Kinase

Studies were made of inhibition by wortmannin, a fungal metabolite, of human platelet responses to various stimuli. Wortmannin at concentrations as low as 1-100 nM inhibited several receptor-agonist-induced 5-hydroxytryptamine release from platelets, without affecting agonist-induced increases in the intracellular concentration of Ca2+. Phorbol 12-myristate 13-acetate (PMA), an active tumour promoter, caused 5-hydroxytryptamine release when combined with a low concentration of ionomycin, and platelet aggregation by itself; these effects of the phorbol ester were also inhibited by wortmannin as well as by staurosporine, a potent, although non-specific, protein kinase C (PKC) inhibitor, in a similar molar concentration range. The platelet responses to the receptor agonists or PMA were accompanied by increased incorporation of [32P]Pi into pleckstrin, a protein selectively expressed in platelets and other blood cells arising from haematopoietic stem cells, as a result of PKC activation in the intact cells. The pleckstrin phosphorylation was inhibited by wortmannin in ways mostly similar to those in which it inhibited the 5-hydroxytryptamine-release responses. Nevertheless, wortmannin failed to inhibit PKC activity measurable in a cell-free assay system which is highly susceptible to staurosporine. Nor did it inhibit the translocation of cytosolic PKC to membranes induced by addition of PMA to platelet cells. Thus wortmannin, which is not a direct inhibitor of PKC, could interfere with the kinase-dependent phosphorylation of pleckstrin, which may play an important role in the cellular responses to receptor stimulation.

Structural organization and chromosomal localization of the mouse Tesk1 (testis-specific protein kinase 1) gene

Gene ◽  
1998 ◽  
Vol 206 (2) ◽  
pp. 237-245 ◽  
Author(s):  
Jiro Toshima ◽  
Kan-ichi Nakagawara ◽  
Mitsuko Mori ◽  
Tetsuo Noda ◽  
Kensaku Mizuno
Keyword(s):  
Protein Kinase ◽  
Structural Organization ◽  
Chromosomal Localization ◽  
Specific Protein ◽  
Specific Protein Kinase

scholarly journals The E1^E4 Protein of Human Papillomavirus Interacts with the Serine-Arginine-Specific Protein Kinase SRPK1

2007 ◽  
Vol 81 (11) ◽  
pp. 5437-5448 ◽  
Author(s):  
Ian Bell ◽  
Ashley Martin ◽  
Sally Roberts
Keyword(s):  
Human Papillomavirus ◽  
Protein Kinase ◽  
Specific Protein ◽  
Replication Cycle ◽  
Differentiated Cells ◽  
Rich Domain ◽  
Productive Phase ◽  
High Level ◽  
Specific Protein Kinase

ABSTRACT Human papillomavirus (HPV) infections of the squamous epithelium are associated with high-level expression of the E1^E4 protein during the productive phase of infection. However, the precise mechanisms of how E1^E4 contributes to the replication cycle of the virus are poorly understood. Here, we show that the serine-arginine (SR)-specific protein kinase SRPK1 is a novel binding partner of HPV type 1 (HPV1) E1^E4. We map critical residues within an arginine-rich domain of HPV1 E1^E4, and in a region known to facilitate E1^E4 oligomerization, that are requisite for SRPK1 binding. In vitro kinase assays show that SRPK1 binding is associated with phosphorylation of an HPV1 E1^E4 polypeptide and modulates autophosphorylation of the kinase. We show that SRPK1 is sequestered into E4 inclusion bodies in terminally differentiated cells within HPV1 warts and that colocalization between E1^E4 and SRPK1 is not dependent on additional HPV1 factors. Moreover, we also identify SRPK1 binding of E1^E4 proteins of HPV16 and HPV18. Our findings indicate that SRPK1 binding is a conserved function of E1^E4 proteins of diverse virus types. SRPK1 influences important biochemical processes within the cell, including nuclear organization and RNA metabolism. While phosphorylation of HPV1 E4 by SRPK1 may directly influence HPV1 E4 function during the infectious cycle, the modulation and sequestration of SRPK1 by E1^E4 may affect the ability of SRPK1 to phosphorylate its cellular targets, thereby facilitating the productive phase of the HPV replication cycle.

scholarly journals Neurogranin: immunocytochemical localization of a brain-specific protein kinase C substrate

1990 ◽  
Vol 10 (12) ◽  
pp. 3782-3792 ◽  
Author(s):  
A Represa ◽  
JC Deloulme ◽  
M Sensenbrenner ◽  
Y Ben-Ari ◽  
J Baudier
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Specific Protein ◽  
Immunocytochemical Localization ◽  
Kinase C ◽  
Specific Protein Kinase

scholarly journals Expression of the mammalian c-fes protein in hematopoietic cells and identification of a distinct fes-related protein.

1985 ◽  
Vol 5 (10) ◽  
pp. 2543-2551 ◽  
Author(s):  
I MacDonald ◽  
J Levy ◽  
T Pawson
Keyword(s):  
Protein Kinase ◽  
Kinase Activity ◽  
Human Peripheral Blood ◽  
Hematopoietic Cells ◽  
Specific Protein ◽  
Protein Kinase Activity ◽  
Sarcoma Virus ◽  
Human And Mouse ◽  
Specific Protein Kinase

The avian c-fps and mammalian c-fes proto-oncogenes are cognate cellular sequences. Antiserum raised against the P140gag-fps transforming protein of Fujinami avian sarcoma virus specifically recognized a 92,000-Mr protein in human and mouse hematopoietic cells which was closely related in structure to Snyder-Theilen feline sarcoma virus P87gag-fes. This polypeptide was apparently the product of the human c-fes gene and was therefore designated p92c-fes. Human p92c-fes was associated with a tyrosine-specific protein kinase activity in vitro and was capable of both autophosphorylation and phosphorylation of enolase as an exogenous protein substrate. The synthesis of human and mouse p92c-fes was largely, though not entirely, confined to myeloid cells. p92c-fes was expressed to relatively high levels in a multipotential murine myeloid cell line, in more mature human and mouse granulocyte-macrophage progenitors, and in differentiated macrophage like cells as well as in the mononuclear fraction of normal and leukemic human peripheral blood. p92c-fes was not found in erythroid cells, with the exception of a human erythroleukemia line which retains the capacity to differentiate into macrophage like cells. These results suggest a normal role for the p92c-fes tyrosine kinase in hematopoiesis, particularly in granulocyte-macrophage differentiation. In addition, a distinct 94,000-Mr polypeptide, antigenically related to p92c-fes, was identified in a number of hematopoietic and nonhematopoietic human and mouse cells and was also found to be associated with a tyrosine-specific protein kinase activity.

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