Differential expression and subcellular localization for subunits of cAMP-dependent protein kinase during ram spermatogenesis.

The expression of mRNAs for the RI alpha, RII alpha, and C alpha subunits of cAMP-dependent protein kinase has been studied in different ram germ cells. The sizes of the specific RI alpha, RII alpha, and C alpha mRNAs, observed in germ cells were 1.6, 2.0, and 2.6 kb, respectively. RI alpha and C alpha mRNAs were mainly expressed in primary spermatocytes. A postmeiotic expression predominating in early spermatids was unique to RII alpha mRNA. The location of RI, RII alpha, and C subunits in well-defined organelles of ram spermatids and epididymal sperm was assessed by immunogold electron microscopy. In spermatids, RI, RII alpha, and C were essentially present in the forming acrosome and, to a lesser extent, in the nucleus. During sperm epididymal maturation, the protein kinases disappeared from the acrosome and were detected in a variety of sperm functional areas, such as the tip of the acrosome, the motility apparatus, and the membrane network. The present study on subunits of cAMP-dependent protein kinase supports the concept that specific functions are attached to the different subunits in that it shows differential expression and differential subcellular localization in germ cells.

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Identification and differential expression of two forms of regulatory subunits (RII) of cAMP-dependent protein kinase II in Friend erythroleukemic cells. Differentiation and 8-bromo-cAMP elicit a large and selective increase in the rate of biosynthesis of only one type of RII.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)88970-0 ◽

1985 ◽

Vol 260 (10) ◽

pp. 6296-6303 ◽

Cited By ~ 7

Author(s):

D A Schwartz ◽

C S Rubin

Keyword(s):

Protein Kinase ◽

Differential Expression ◽

Dependent Protein Kinase ◽

Regulatory Subunits ◽

Camp Dependent Protein Kinase ◽

Protein Kinase Ii ◽

Dependent Protein ◽

Friend Erythroleukemic Cells ◽

Selective Increase ◽

Erythroleukemic Cells

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Type II regulatory subunit dimerization determines the subcellular localization of the cAMP-dependent protein kinase.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)45777-8 ◽

1990 ◽

Vol 265 (35) ◽

pp. 21561-21566 ◽

Cited By ~ 5

Author(s):

J D Scott ◽

R E Stofko ◽

J R McDonald ◽

J D Comer ◽

E A Vitalis ◽

...

Keyword(s):

Protein Kinase ◽

Subcellular Localization ◽

Regulatory Subunit ◽

Type Ii ◽

Dependent Protein Kinase ◽

Camp Dependent Protein Kinase ◽

Dependent Protein

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Localization of nuclear subunits of cyclic AMP-dependent protein kinase by the immunocolloidal gold method.

The Journal of Cell Biology ◽

10.1083/jcb.101.3.965 ◽

1985 ◽

Vol 101 (3) ◽

pp. 965-975 ◽

Cited By ~ 36

Author(s):

M R Kuettel ◽

S P Squinto ◽

J Kwast-Welfeld ◽

G Schwoch ◽

J S Schweppe ◽

...

Keyword(s):

Electron Microscopy ◽

Protein Kinase ◽

Hepatoma Cells ◽

Catalytic Subunit ◽

Immunogold Electron Microscopy ◽

Dependent Protein Kinase ◽

Regulatory Subunits ◽

Camp Dependent Protein Kinase ◽

Specific Antisera ◽

Dependent Protein

An immunocolloidal gold electron microscopy method is described allowing the ultrastructural localization and quantitation of the regulatory subunits RI and RII and the catalytic subunit C of cAMP-dependent protein kinase. Using a postembedding indirect immunogold labeling procedure that employs specific antisera, the catalytic and regulatory subunits were localized in electron-dense regions of the nucleus and in cytoplasmic areas with a minimum of nonspecific staining. Antigenic domains were localized in regions of the heterochromatin, nucleolus, interchromatin granules, and in the endoplasmic reticulum of different cell types, such as rat hepatocytes, ovarian granulosa cells, and spermatogonia, as well as cultured H4IIE hepatoma cells. Morphometric quantitation of the relative staining density of nuclear antigens indicated a marked modulation of the number of subunits per unit area under various physiologic conditions. For instance, following partial hepatectomy in rats, the staining density of the nuclear RI and C subunits was markedly increased 16 h after surgery. Glucagon treatment of rats increased the staining density of only the nuclear catalytic subunit. Dibutyryl cAMP treatment of H4IIE hepatoma cells led to a marked increase in the nuclear staining density of all three subunits of cAMP-dependent protein kinase. These studies demonstrate that specific antisera against cAMP-dependent protein kinase subunits may be used in combination with immunogold electron microscopy to identify the ultrastructural location of the subunits and to provide a semi-quantitative estimate of their relative cellular density.

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