Protocadherin-18 (Pcdh18) belongs to the delta-2 subfamily of nonclustered protocadherins (comprising protocadherin-8, -10, -17, -18, and -19) []. Zebrafish has two Pcdh18 isoforms, Pcdh18a and Pcdh18b. Pcdh18a has a role in cell adhesion and migration [], whereas Pcdh18b interacts with Nap1, an important regulator of actin dynamics, to control motor axon growth and arborisation in primary motoneurons []. In mouse, Pcdh18 interacts with Disabled-1 (Dab1) and may play a role during brain development [].The cadherin family consists of a large group of cell adhesion proteins. It can be classified into three subfamilies: classical cadherins, desmosomal cadherins and protocadherins (PCDHs). Based on the genomic structure, the PCDH family can be divided into two groups, clustered PCDHs and non-clustered PCDHs. Non-clustered PCDHs can be further classified into three subgroups: delta1 (PCDH1, PCDH7, PCDH9, PCDH11 and PCDH20), delta2 (PCDH8, PCDH10, PCDH12, PCDH17, PCDH18 and PCDH19) and epsilon (PCDH15, PCDH16, PCDH21 and MUCDHL). Non-clustered PCDHs are expressed predominantly in the nervous system and have spatiotemporally diverse expression patterns [].
Protocadherin-12 (Pcdh12), also known as vascular cadherin-2 or VE-cadherin-2, is located at the intercellular junctions of endothelial cells, where it promotes homotypic cellular adhesion []. It is required for placental development [, ]and its deficiency leads to modifications in the structure and function of arteries in adult mice [].The cadherin family consists of a large group of cell adhesion proteins. It can be classified into three subfamilies: classical cadherins, desmosomal cadherins and protocadherins (PCDHs). Based on the genomic structure, the PCDH family can be divided into two groups, clustered PCDHs and non-clustered PCDHs. Non-clustered PCDHs can be further classified into three subgroups: delta1 (PCDH1, PCDH7, PCDH9, PCDH11 and PCDH20), delta2 (PCDH8, PCDH10, PCDH12, PCDH17, PCDH18 and PCDH19) and epsilon (PCDH15, PCDH16, PCDH21 and MUCDHL). Non-clustered PCDHs are expressed predominantly in the nervous system and have spatiotemporally diverse expression patterns [].
Protocadherin-10 (Pcdh10) belongs to the delta-2 subfamily of nonclustered protocadherins []. Pcdh10 is a pivotal tumour suppressor in colorectal cancer []and induces myeloma cell apoptosis, probably by inhibiting the NF-kappaB pathway [].The cadherin family consists of a large group of cell adhesion proteins. It can be classified into three subfamilies: classical cadherins, desmosomal cadherins and protocadherins (PCDHs). Based on the genomic structure, the PCDH family can be divided into two groups, clustered PCDHs and non-clustered PCDHs. Non-clustered PCDHs can be further classified into three subgroups: delta1 (PCDH1, PCDH7, PCDH9, PCDH11 and PCDH20), delta2 (PCDH8, PCDH10, PCDH12, PCDH17, PCDH18 and PCDH19) and epsilon (PCDH15, PCDH16, PCDH21 and MUCDHL). Non-clustered PCDHs are expressed predominantly in the nervous system and have spatiotemporally diverse expression patterns [].
Protocadherin-8 (Pcdh8) belongs to the delta-2 subfamily of nonclustered protocadherins [, ]. It is involved in development [, ]and can act as a tumour suppressor [, ].The cadherin family consists of a large group of cell adhesion proteins. It can be classified into three subfamilies: classical cadherins, desmosomal cadherins and protocadherins (PCDHs). Based on the genomic structure, the PCDH family can be divided into two groups, clustered PCDHs and non-clustered PCDHs. Non-clustered PCDHs can be further classified into three subgroups: delta1 (PCDH1, PCDH7, PCDH9, PCDH11 and PCDH20), delta2 (PCDH8, PCDH10, PCDH12, PCDH17, PCDH18 and PCDH19) and epsilon (PCDH15, PCDH16, PCDH21 and MUCDHL). Non-clustered PCDHs are expressed predominantly in the nervous system and have spatiotemporally diverse expression patterns [].
Protocadherin-15 (Pcdh15) belongs to the epsilon subfamily of nonclustered protocadherins. It is a component of the tip-links, the extracellular filaments that connect the tips of stereocilia and gate hair cell mechano-electrical transduction channels in the inner ear []. Pcdh15 interacts with transmembrane channel-like proteins TMC1 and TMC2, which have been implicated in mechanotransduction in mammalian hair cells []. Mutations in genes coding for Pcdh15 cause deafness in both mice and humans [, ]. Pcdh15 plays an important role in hair-bundle morphogenesis [].The cadherin family consists of a large group of cell adhesion proteins. It can be classified into three subfamilies: classical cadherins, desmosomal cadherins and protocadherins (PCDHs). Based on the genomic structure, the PCDH family can be divided into two groups, clustered PCDHs and non-clustered PCDHs. Non-clustered PCDHs can be further classified into three subgroups: delta1 (PCDH1, PCDH7, PCDH9, PCDH11 and PCDH20), delta2 (PCDH8, PCDH10, PCDH12, PCDH17, PCDH18 and PCDH19) and epsilon (PCDH15, PCDH16, PCDH21 and MUCDHL). Non-clustered PCDHs are expressed predominantly in the nervous system and have spatiotemporally diverse expression patterns [].
Protocadherin-19 (Pcdh19) belongs to the delta-2 subfamily of nonclustered protocadherins. The non-clustered PCDHs appear to have homophilic/heterophilc cell-cell adhesion properties [], and the delta-2 subfamily (comprising protocadherin-8, -10, -17, -18, and -19) is widely expressed in the nervous system [, ]. Pcdh19 is highly expressed during brain development, and could play significant roles in neuronal migration or establishment of synaptic connections. Pcdh19 mutations cause an unusual X-linked inheritance disorder resulting in epilepsy and mental retardation [, , ].The cadherin family consists of a large group of cell adhesion proteins. It can be classified into three subfamilies: classical cadherins, desmosomal cadherins and protocadherins (PCDHs). Based on the genomic structure, the PCDH family can be divided into two groups, clustered PCDHs and non-clustered PCDHs. Non-clustered PCDHs can be further classified into three subgroups: delta1 (PCDH1, PCDH7, PCDH9, PCDH11 and PCDH20), delta2 (PCDH8, PCDH10, PCDH12, PCDH17, PCDH18 and PCDH19) and epsilon (PCDH15, PCDH16, PCDH21 and MUCDHL). Non-clustered PCDHs are expressed predominantly in the nervous system and have spatiotemporally diverse expression patterns [].
Protocadherin-17 (Pcdh17) belongs to the delta-2 subfamily of nonclustered protocadherins. The non-clustered PCDHs appear to have homophilic/heterophilc cell-cell adhesion properties [], and the delta-2 subfamily (comprising protocadherin-8, -10, -17, -18, and -19) is widely expressed in the nervous system [, ]. Pcdh17 mediates collective axon extension in amygdala neurons [], regulates presynaptic assembly in corticobasal ganglia circuits [], and is involved in brain vascular development []. In addition, it has been shown to have a role in the formation of the zebrafish retina []and to act as a tumour suppressor [, ].The cadherin family consists of a large group of cell adhesion proteins. It can be classified into three subfamilies: classical cadherins, desmosomal cadherins and protocadherins (PCDHs). Based on the genomic structure, the PCDH family can be divided into two groups, clustered PCDHs and non-clustered PCDHs. Non-clustered PCDHs can be further classified into three subgroups: delta1 (PCDH1, PCDH7, PCDH9, PCDH11 and PCDH20), delta2 (PCDH8, PCDH10, PCDH12, PCDH17, PCDH18 and PCDH19) and epsilon (PCDH15, PCDH16, PCDH21 and MUCDHL). Non-clustered PCDHs are expressed predominantly in the nervous system and have spatiotemporally diverse expression patterns [].
