How clustered protocadherin binding specificity is tuned for neuronal self-/nonself-recognition.

Area of Science:

• Neuroscience
• Molecular Biology
• Biophysics

Background:

• Clustered protocadherins (cPcdhs) are crucial for neuronal identity and self/non-self discrimination in vertebrates.
• cPcdhs form cell-surface chains via cis and trans interactions, hypothesized to mediate self-recognition.

Purpose of the Study:

• To investigate the biophysical properties of clustered protocadherin (cPcdh) cis and trans interactions.
• To determine if cPcdh cis dimerization is promiscuous and if trans interactions are specific, as required for neuronal self-recognition.

Main Methods:

• Biophysical experiments including crystal structure determination of a C-type cPcdh.
• Mutagenesis studies to probe interaction mechanisms.

Main Results:

• cPcdh cis interactions are promiscuous, with a preference for heterologous cis dimer formation.
• cPcdh trans interactions are highly specific and homophilic, with no observed heterophilic interactions between different isoforms.
• Structural and mutagenesis data provide mechanistic insights into these interaction preferences.

Conclusions:

• The interaction characteristics of cPcdhs support their role in neuronal self/non-self discrimination.
• Promiscuous cis dimerization and specific trans homophilic interactions enable the generation of diverse recognition units for neuronal wiring.