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        30        40
                 ....*....|....*....|....*....|....*....|..
gi 767970271   9 HYRIPQGFGNLLEGLTREILREQPDNIPAFAAAYFESLLEKR 50
Cdd:cd12100    1 RLRLPYGLKSLLEGLSREVLREQPEDIPEFAADYFEELLKFR 42

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        30        40
                 ....*....|....*....|....*....|....*....|..
gi 767970271   9 HYRIPQGFGNLLEGLTREILREQPDNIPAFAAAYFESLLEKR 50
Cdd:cd12100    1 RLRLPYGLKSLLEGLSREVLREQPEDIPEFAADYFEELLKFR 42

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        30
                   ....*....|....*....|....*....|....*...
gi 767970271    14 QGFGNLLEGLTREILREQPDNIPAFAAAYFESLLEKRE 51
Cdd:smart00394   1 HGLQALLEDLTVEVLRAQPSDLVQFAADYFEKLEEQRA 38

Calmodulin-binding motif; Short calmodulin-binding motif containing conserved Ile and Gln residues.

                           10
                   ....*....|....*....
gi 767970271   117 AAVKIQAAFRGHIAREEAK 135
Cdd:smart00015   5 AAIIIQAAWRGYLARKRYK 23

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        30        40
                 ....*....|....*....|....*....|....*....|..
gi 767970271   9 HYRIPQGFGNLLEGLTREILREQPDNIPAFAAAYFESLLEKR 50
Cdd:cd12100    1 RLRLPYGLKSLLEGLSREVLREQPEDIPEFAADYFEELLKFR 42

Regulatory subunit of type II PKA R-subunit;

                          10        20        30
                  ....*....|....*....|....*....|....*..
gi 767970271   14 QGFGNLLEGLTREILREQPDNIPAFAAAYFESLLEKR 50
Cdd:pfam02197   1 HGLQALLEDLTVEVLRAQPSDPLQFAADYFEKLEEER 37

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 767970271  12 IPQGFGNLLEGLTREILREQPDNIPAFAAAYFESLL 47
Cdd:cd12084    1 VPEGLRELLEDFTREVLREQPEDVYEFAADYFEKLL 36

dimerization/docking (D/D) domain found in the ropporin (ROP)-like subfamily; The ROP-like family includes ropporin-1A (ROP1A, also called cancer/testis antigen 91, CT91, or rhophilin-associated protein 1A), ropporin-1B (ROP1B, also called rhophilin-associated protein 1B), and ropporin-1-like protein (ROPN1L, also called ROPN1-like protein, AKAP-associated sperm protein, or ASP), as well as Chlamydomonas reinhardtii flagellar radial spoke proteins, RSP7 and RSP11. ROP1A, ROP1B and ROPN1L play important roles in male fertility. They are involved in fibrous sheath integrity and sperm motility and play roles in cAMP-dependent protein kinase (PKA)-dependent signaling processes required for spermatozoa capacitation. RSP7 is a PKA RII-like protein. RSP11 is a non-PKA RIIa protein that contains a RII domain but lack any features required for cAMP signaling or phosphorylation. It is involved in the control of ciliary and flagellar beating. Members of this subfamily contain a conserved helical bundle domain that shows high sequence similarity to the dimerization/docking (D/D) domain of the regulatory subunit of PKA.

                         10        20        30
                 ....*....|....*....|....*....|....*
gi 767970271  12 IPQGFGNLLEGLTREILREQPDNIPAFAAAYFESL 46
Cdd:cd22972    6 IPEGLPEILKAYAKEAIRSQPEDLIQWSAKYFRAL 40

dimerization/docking (D/D) domain found in Saccharomyces cerevisiae cAMP-dependent protein kinase regulatory subunit 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. The R subunit of fungal PKA is encoded by a single gene, which is called by various names in different organisms (for example: Yarrowia lipolytica RKA1, Saccharomyces cerevisiae Bcy1, and Schizosaccharomyces pombe Cgs1). Although most characterized PKA holoenzymes are tetramers, Y. lipolytica PKA has been reported to be a dimer of RKA1 and the catalytic subunit TPK1. RKA1 is essential and promotes hyphal growth. Cgs1 is essential for sexual differentiation of S. pombe; mutants with defective Cgs1 are partially sterile. 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 of metazoan R subunits dimerizes to form a four-helix bundle that serves as a docking site for A-kinase-anchoring proteins (AKAPs). The D/D domain of fungal R subunits may also serve as a dimerization domain, in the case of heterotetrameric PKAs. Fungal PKA plays a major role in controlling cell growth and metabolism in response to nutrients and stress conditions.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|..
gi 767970271  12 IPQGFGNLLEGLTREILREQPDNIPAFAAAYFESLLEKREKT 53
Cdd:cd12098    1 LPSEYPDELNELNREVLRAQPDDILQFCANYFNRKLEEQRAF 42

dimerization/docking (D/D) domain found in RIIa domain-containing protein 1 (RIIAD1) and similar proteins; The family includes uncharacterized RIIa domain-containing protein 1 (RIIAD1), which contains a C-terminal domain that shows high sequence similarity to the dimerization/docking (D/D) domain of regulatory subunit of cAMP-dependent protein kinase (PKA).

                         10        20
                 ....*....|....*....|....*
gi 767970271  19 LLEGLTREILREQPDNIPAFAAAYF 43
Cdd:cd22971    9 LISGFLREVLKKKPENIREFAAEFF 33

IQ (isoleucine-glutamine) motif containing D (IQCD); IQCD, also called dynein regulatory complex protein 10 (DRC10), belongs to the IQ motif-containing protein family which contains a C-terminal conserved IQ motif domain and two coiled-coil domains. The IQ motif ([ILV]QxxxRxxxx[RK]), where x stands for any amino-acid residue, interacts with calmodulin (CaM) in a calcium-independent manner and is present in proteins with a wide diversity of biological functions. The IQCD protein was found to primarily accumulate in the acrosome area of round and elongating spermatids of the testis during late stage of spermiogenesis and was then localized to the acrosome and tail regions of mature spermatozoa. The expression of IQCD follows the trajectory of acrosome development during spermatogenesis. IQCD is associated with neuroblastoma and neurodegenerative diseases, and is reported to interact with the nuclear retinoid X receptor in the presence of 9-cis-retinoic acid, thereby activating the transcriptional activity of the receptor.

                         10        20
                 ....*....|....*....|..
gi 767970271 117 AAVKIQAAFRGHIAREEAKKMK 138
Cdd:cd23767   11 AATLIQALWRGYKVRKELKKKK 32

IQ calmodulin-binding motif; Calmodulin-binding motif.

                          10
                  ....*....|....*....
gi 767970271  117 AAVKIQAAFRGHIAREEAK 135
Cdd:pfam00612   3 AAIKIQAAWRGYLARKRYK 21