Table 5.

Key interaction contacts in the CAPN1/CAST4 complex.

The regulation system	Interaction regions	Calpain residues *
The catalytic subunit of CAPN1/subdomains AB of CAST4 complex from both bovines (model structure)	CAPN1 and CAST4 subdomain B	Leu73, Ser78, Lys79, Ile83, Cys108, Gln109, Gly110, Ala111, Leu112, Gly113, Cys115, Trp116, Lys171, Lys174, Leu175, Val176, His179, Ser209, Thr210, Glu212, Ser251, Asp253, Ile254, Ser255, Ser256, Asp259, Met260, Ala262, Val263, Val269, Lys270, Gly271, His272, Ala273, Trp298, Glu300, Arg347, Glu349, Cys384, Arg385, Asn386, Pro388, Trp392, Asp439, Met440, Thr442, Tyr448, Lys463, Asp465, Phe467, Leu468, Ser469, Asn470, Ala471, Ser472, Arg475, Gln478, Phe479, Ile480, Asn481, Leu482, Arg483, Phe503
	CAPN1 and CAST4 subdomain A	Asn548, Leu552, Gln555, Leu556, Ile571, Arg574, Ile575, Lys578, His579, Asp581, Phe612, Trp616, Ile619, Arg620, Leu623, Arg627, Asp630, Leu631, Lys633, Gly635
The overall CAPN2/CAST4 complex from both rats (PDB ID: 3BOW)	CAP2 and CAST4 subdomain B	Leu63, Gly100, Ala101, Leu102, Lys161, Leu169, Gly198, Ile244, Thr245, Asp249, Gly261, His262, Ala263, Trp288, Arg375, Asn376, Leu454, Thr455, Arg457, Ala458, Arg461, Phe465, Asn467, Phe489
	CAP2 and CAST4 subdomain A	Leu537, Gln540, Leu541, Ile556, Val560, Arg564, Trp601, Gln605, Gln608, Arg612, Asp615
	CAP2 and CAST4 subdomain C	Leu106, Leu110, Ile125, Val129, Arg132, His133, Trp170

^*Interaction sites by residue character: class-specific (blue) and bovine only species-specific (red) trace residues.