UNIPROT #

P17612

PROTEIN NAME

PKA C alpha

SYNONYMS

cAMP dependent protein kinase beta catalytic subunit antibody; cAMP dependent protein kinase alpha catalytic subunit antibody; cAMP dependent protein kinase catalytic subunit alpha antibody; cAMP dependent protein kinase catalytic subunit beta antibody; PKA C alpha antibody; PKA C beta antibody; PKACA antibody; PKACB antibody; PRKACA antibody; PRKACB antibody; Protein kinase cAMP dependent catalytic alpha antibody; Protein kinase cAMP dependent catalytic beta antibody

SEQUENCE SIMILARITIES

Belongs to the protein kinase superfamily. AGC Ser/Thr protein kinase family. cAMP subfamily.

TISSUE SPECIFICITY

Isoform 1 is ubiquitous. Isoform 2 is sperm-specific and is enriched in pachytene spermatocytes but is not detected in round spermatids.

POST-TRANSLATIONAL MODIFICATION

Asn-3 is partially deaminated to Asp giving rise to 2 major isoelectric variants, called CB and CA respectively.; Autophosphorylated. Phosphorylation is enhanced by vitamin K(2). Phosphorylated on threonine and serine residues. Phosphorylation on Thr-198 is required for full activity.; Phosphorylated at Tyr-331 by activated receptor tyrosine kinases EGFR and PDGFR; this increases catalytic efficiency.

SUBCELLULAR LOCATION

Mitochondrion. Nucleus.Plasma membrane.

FUNCTION

The second messenger cyclic AMP (cAMP) mediates diverse cellular responses to external signals such as proliferation, ion transport, regulation of metabolism and gene transcription by activation of the cAMP-dependent protein kinase (cAPK or PKA). Activation of PKA occurs when cAMP binds to the two regulatory subunits of the tetrameric PKA holoenzyme resulting in release of active catalytic subunits. Three catalytic (C) subunits have been identified, designated Cα, Cβ and Cγ, that each represent specific gene products. Cα and Cβ are closely related (93% amino acid sequence similarity), whereas Cγ displays 83% and 79% similarity to Cα and Cβ, respectively. Activation of transcription upon elevation of cAMP levels results from translocation of PKA to the nucleus where it phosphorylates the transcription factor cAMP response element binding protein (CREB) on serine 133 which in turn leads to TFIIB binding to TATA-box-binding protein TBP1, thus linking phospho-CREB to the pol II transcription initiation complex.