Regulatory subunit of type II PKA R-subunit;

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                  ....*....|....*....|....*.
gi 2217266671  58 LISGFFREIFLKRPDNILEFAADYFT 83
Cdd:pfam02197   6 LLEDLTVEVLRAQPSDPLQFAADYFE 31

dimerization/docking (D/D) domain of the type II Regulatory subunit of cAMP-dependent protein kinase and similar domains; cAMP-dependent protein kinase (PKA) is a serine/threonine kinase (STK), catalyzing the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. The inactive PKA holoenzyme is a heterotetramer composed of two phosphorylated and active catalytic subunits with a dimer of regulatory (R) subunits. Activation is achieved through the binding of the important second messenger cAMP to the R subunits, which leads to the dissociation of PKA into the R dimer and two active subunits. There are two classes of R subunits, RI and RII; each exists as two isoforms (alpha and beta) from distinct genes. These functionally non-redundant R isoforms allow for specificity in PKA signaling. The R subunit contains an N-terminal dimerization/docking (D/D) domain, a linker with an inhibitory sequence (IS), and two c-AMP binding domains. RI and RII subunits are distinguished by their IS; RII subunits contain a phosphorylation site and are both substrates and inhibitors while RI subunits are pseudo-substrates. RI subunits require ATP and Mg ions to form a stable holoenzyme while RII subunits do not. The D/D domain dimerizes to form a four-helix bundle that serves as a docking site for A-kinase-anchoring proteins (AKAPs), which facilitates the localization of PKA to specific sites in the cell. PKA is present ubiquitously in cells and interacts with many different downstream targets. It plays a role in the regulation of diverse processes such as growth, development, memory, metabolism, gene expression, immunity, and lipolysis.

                          10        20        30
                  ....*....|....*....|....*....|...
gi 2217266671  52 HKEVEWLISGFFREIFLKRPDNILEFAADYFTD 84
Cdd:cd12084     2 PEGLRELLEDFTREVLREQPEDVYEFAADYFEK 34

dimerization/docking (D/D) domain of the sperm fibrous sheath proteins, Calcium-Binding tYrosine-phosphorylation Regulated protein and Sperm Protein 17; CABYR and SP17 are naturally located in the human sperm fibrous sheath (FS). CABYR was originally isolated from spermatoza and was thought to be testis-specific, but has recently been observed in lung and brain tumors. It is a polymorphic calcium binding protein that is phosphorylated during capacitation. SP17 plays an important role in the interaction of sperm with the zona pellucida during fertilization. It also promotes cell-cell adhesion. SP17 is found in various human tumors of unrelated histological origin including metastatic squamous cell carcinoma, multiple myeloma, ovarian cancer, and primary nervous system tumors, among others. Both CABYR and SP17 contain an N-terminal dimerization/docking (D/D) domain with similarity to the D/D domain of the R subunit of cAMP-dependent protein kinase (PKA). The D/D domain of the R subunit dimerizes to form a four-helix bundle that serves as a docking site for A-kinase-anchoring proteins (AKAPs), which facilitates the localization of PKA to specific sites in the cell. The D/D domain of CABYR and SP17 have been shown to bind to AKAP3, a protein that is also associated to the FS of mammalian spermatozoa.

                          10        20
                  ....*....|....*....|....*..
gi 2217266671  58 LISGFFREIFLKRPDNILEFAADYFTD 84
Cdd:cd12100    11 LLEGLSREVLREQPEDIPEFAADYFEE 37

RIIalpha, Regulatory subunit portion of type II PKA R-subunit; RIIalpha, Regulatory subunit portion of type II PKA R-subunit. Contains dimerisation interface and binding site for A-kinase-anchoring proteins (AKAPs).

                           10        20
                   ....*....|....*....|....*.
gi 2217266671   58 LISGFFREIFLKRPDNILEFAADYFT 83
Cdd:smart00394   6 LLEDLTVEVLRAQPSDLVQFAADYFE 31

dimerization/docking (D/D) domain of the Type II Regulatory subunit of cAMP-dependent protein kinase; cAMP-dependent protein kinase (PKA) is a serine/threonine kinase (STK), catalyzing the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. The inactive PKA holoenzyme is a heterotetramer composed of two phosphorylated and active catalytic subunits with a dimer of regulatory (R) subunits. Activation is achieved through the binding of the important second messenger cAMP to the R subunits, which leads to the dissociation of PKA into the R dimer and two active subunits. There are two classes of R subunits, RI and RII; each exists as two isoforms (alpha and beta) from distinct genes. These functionally non-redundant R isoforms allow for specificity in PKA signaling. RII subunits contain a phosphorylation site in their inhibitory site and are both substrates and inhibitors. RIIalpha plays a role in the association and dissociation of PKA with the centrosome during interphase and mitosis, respectively. RIIbeta plays an important role in adipocytes and neuronal tissues. The R subunit contains an N-terminal dimerization/docking (D/D) domain, a linker with an inhibitory sequence, and two c-AMP binding domains. The D/D domain dimerizes to form a four-helix bundle that serves as a docking site for A-kinase-anchoring proteins (AKAPs), which facilitates the localization of PKA to specific sites in the cell. PKA is present ubiquitously in cells and interacts with many different downstream targets. It plays a role in the regulation of diverse processes such as growth, development, memory, metabolism, gene expression, immunity, and lipolysis.

                          10        20
                  ....*....|....*....|....*.
gi 2217266671  58 LISGFFREIFLKRPDNILEFAADYFT 83
Cdd:cd12099     8 LLQDFTVAVLREQPTDLVDFAAEYFT 33