Difference between revisions of "Kinase Family PKA"

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[[kinase classification|Kinase Classification]]: [[Kinase_Group_AGC|Group AGC]]: [[Kinase_Family_PKA|Family PKA]]
 
[[kinase classification|Kinase Classification]]: [[Kinase_Group_AGC|Group AGC]]: [[Kinase_Family_PKA|Family PKA]]
  
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Protein Kinase A ('''PKA''') is a '''cAMP-dependent protein kinase''' with many cellular functions. It is activated by cAMP binding to its regulatory subunit, which then activates the catalytic subunit. In basal organisms, these two subunits may be fused.
  
The PKA family has two putative subfamlies: PKA, and PRKX.
 
  
=====PRKA=====
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The PKA family has the following subfamilies
Protein Kinase A is the best known structural and mechanistic model for the ePK superfamily. Three members are found in human, and the gene is found in most eukaryotes. It is activated by cyclic AMP and mediates a wide number of signaling functions.
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====[[Kinase_Subfamily_PKA|Subfamily PKA]]====
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Protein Kinase A is the best known structural and mechanistic model for the ePK superfamily. Three members are found in human, and the gene is found in most eukaryotes. It is activated by cyclic AMP and mediates a wide number of signaling functions.
  
=====PRKX=====
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====[[Kinase_Subfamily_PKX|Subfamily PKX]]====
In human, this consists of PRKX, on the X chromosome, and PRKY, a possible pseudogene found on the Y chromosome. Preliminary analysis indicates that distinct PRKX genes (as opposed to PKA family genes) are found in both Drosophila and C. elegans.
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In human, this consists of PRKX, on the X chromosome, and [[Kinase_PRKY|PRKY]], a possible pseudogene found on the Y chromosome. Preliminary analysis indicates that distinct PRKX genes (as opposed to PKA family genes) are found in both Drosophila and C. elegans.
  
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====[[Kinase_Subfamily_PKAHP|Subfamily PKAHP]]====
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This subfamily is found in land plants, at least one alga and stramenopiles (oomycetes). It consists of a PP2C phosphatase domain followed by a pair of cNMP-binding domains that are most similar to those of the PKA catalytic subunit, followed by a kinase domain that is most similar to the PKA catalytic subunit, but which has multiple changes that suggest it is a [[pseudokinases|pseudokinase]]. These proteins are often annotated as [[Kinase_Family_PKG|PKG]] since they contain both cNMP-binding and kinase domains in the one polypeptide, and PKG proteins are typically their best blast hits.
  
=====PRKY details=====
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====[[Other_Basal_PKA|Other Basal PKA]]====
Human PRKY has lost the 6th coding exon from the genome, and 10 ESTs and cDNAs confirm that the transcript splices from exon 5 to exon 7, resulting in a frameshift and premature stop to the ORF. This change removes the last 31 AA of the kinase domain and the PKC-Cterminal domain. The chimp retains exon 6 and appears to encode a full length gene. No other homologs have been found in cDNA/EST databases, whole genome shotgun datasets or in assembled genomes, though Y chromosomes are frequently not sequenced or undersequenced (if the samples are not all male) or are poorly assembled due to their highly repetitive nature. Comparison of the chimp and human ORFs upstream of the deleted exon, with PRKX from several primates, suggests that PRKY is not under purifying selection in human, and may even be under positive selection in chimp, though the numbers are very low.
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Several basal eukaryotic lineages have kinases that contain both cNMP-binding and kinase domains, with the domains most similar to those of animal PKA, but the domain arrangement similar to that of PKG. These have not yet been placed in defined subfamilies.
  
--[[User:Gerard|Gerard]] 13:48, 27 May 2010 (PDT)
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[[User:Gerard|Gerard]] 00:26, 8 March 2012 (UTC)

Latest revision as of 01:04, 6 January 2022

Kinase Classification: Group AGC: Family PKA

Protein Kinase A (PKA) is a cAMP-dependent protein kinase with many cellular functions. It is activated by cAMP binding to its regulatory subunit, which then activates the catalytic subunit. In basal organisms, these two subunits may be fused.


The PKA family has the following subfamilies

Subfamily PKA

Protein Kinase A is the best known structural and mechanistic model for the ePK superfamily. Three members are found in human, and the gene is found in most eukaryotes. It is activated by cyclic AMP and mediates a wide number of signaling functions.

Subfamily PKX

In human, this consists of PRKX, on the X chromosome, and PRKY, a possible pseudogene found on the Y chromosome. Preliminary analysis indicates that distinct PRKX genes (as opposed to PKA family genes) are found in both Drosophila and C. elegans.

Subfamily PKAHP

This subfamily is found in land plants, at least one alga and stramenopiles (oomycetes). It consists of a PP2C phosphatase domain followed by a pair of cNMP-binding domains that are most similar to those of the PKA catalytic subunit, followed by a kinase domain that is most similar to the PKA catalytic subunit, but which has multiple changes that suggest it is a pseudokinase. These proteins are often annotated as PKG since they contain both cNMP-binding and kinase domains in the one polypeptide, and PKG proteins are typically their best blast hits.

Other Basal PKA

Several basal eukaryotic lineages have kinases that contain both cNMP-binding and kinase domains, with the domains most similar to those of animal PKA, but the domain arrangement similar to that of PKG. These have not yet been placed in defined subfamilies.

Gerard 00:26, 8 March 2012 (UTC)