IQ (isoleucine-glutamine) motif containing G and D (IQCG and IQCD); IQCG and IQCD belong to the IQ motif-containing protein family which contain a C-terminal conserved IQ (isoleucine-glutamine) motif and a coiled-coil domain. The IQCG protein (also known as DRC9 and CFAP122) is essential for sperm flagellum formation in mice. The IQCD protein (also known as DRC10) is involved in sperm fertilization and the acrosome reaction. Both proteins are components of the nexin-dynein regulatory complex (N-DRC), a key regulator of ciliary/flagellar motility. IQCG and IQCD proteins contain a central coiled-coil domain and a C-terminal IQ (isoleucine-glutamine) motif ([ILV]QxxxRxxxx[RK]), where x stands for any amino-acid residue, that interacts with calmodulin (CaM) in a calcium-independent manner. IQ motif-containing proteins that are known to bind calmodulin (CaM) have a wide diversity of biological functions, and they include neuronal growth proteins, myosins, voltage-operated channels, phosphatases, Ras exchange proteins, sperm surface proteins, Ras Gap-like proteins, spindle-associated proteins, and several proteins in plants.

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                 ....*....|....*....|
gi 219521695  32 KRVKAAGQIQAWWRGVLVRR 51
Cdd:cd23766    9 LELRAAIKIQAWWRGIMVRK 28

IQ (isoleucine-glutamine) motif containing G (IQCG); IQCG, also called dynein regulatory complex protein 9 (DRC9), belongs to the IQ motif-containing protein family which contains a C-terminal conserved IQ (isoleucine-glutamine) motif and a coiled-coil domain. 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 expression of IQCG is reduced in the sperm of human asthenospermia patients whose sperm have reduced mobility. It has also been shown to have a role in the calmodulin-mediated calcium signaling pathway in zebrafish haematopoietic development. The human IQCG gene was first reported to be involved in chromosome translocation in a case of acute lymphoid/myeloid leukemia. It expresses predominantly at mice testis during spermatogenesis which interacts with calmodulin in a calcium-dependent manner in the mouse testis. IQCG knockout mice are sterile due to the total immobility of their spermatozoa.

                         10        20
                 ....*....|....*....|
gi 219521695  32 KRVKAAGQIQAWWRGVLVRR 51
Cdd:cd23766    9 LELRAAIKIQAWWRGIMVRK 28

IQ (isoleucine-glutamine) motif containing G (IQCG); IQCG, also called dynein regulatory complex protein 9 (DRC9), belongs to the IQ motif-containing protein family which contains a C-terminal conserved IQ (isoleucine-glutamine) motif and a coiled-coil domain. 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 expression of IQCG is reduced in the sperm of human asthenospermia patients whose sperm have reduced mobility. It has also been shown to have a role in the calmodulin-mediated calcium signaling pathway in zebrafish haematopoietic development. The human IQCG gene was first reported to be involved in chromosome translocation in a case of acute lymphoid/myeloid leukemia. It expresses predominantly at mice testis during spermatogenesis which interacts with calmodulin in a calcium-dependent manner in the mouse testis. IQCG knockout mice are sterile due to the total immobility of their spermatozoa.

                         10        20
                 ....*....|....*....|
gi 219521695  32 KRVKAAGQIQAWWRGVLVRR 51
Cdd:cd23766    9 LELRAAIKIQAWWRGIMVRK 28