Table I. List of proteins processed by CCP1 at their gene-encoded C-terminus.

Protein	Accession number	Assay	Identified neo-C-terminus	Cleaved amino acids	L/H ratio	Subcellular Localization	Function
α-tubulin 1A/1B	Q71U36/P68363	C-terminal COFRADIC	EDMAALEKDYEEVGVDSVEGEGEEEG	EE(Y)a	N/A	Cytoplasm	Microtubules
α-tubulin 1C	Q9BQE3	C-terminal COFRADIC	EDMAALEKDYEEVGADSADGEDEG	EE(Y)a	N/A	Cytoplasm	Microtubules
Eukaryotic translation initiation factor 4H	Q15056	C-terminal COFRADIC	EEVVQKEQ	E	N/A	Cytoplasm	Translation initiation
Stathmin	P16949	C-terminal COFRADIC	KNKESKDPADETEA	D	0.029	Cytoplasm	Microtubules regulation
40S ribosomal protein S9	P46781	C-terminal COFRADIC	KNAKKGQGGAGAGDDE	EED	N/A	Cytoplasm	Translation initiation
		C-terminal COFRADIC	KNAKKGQGGAGAGDD	EEED	N/A
TRAF-type zinc finger domain-containing protein	O14545	C-terminal COFRADIC	TAKAKPSKQQGAGDA	EEEEEE	0.14	Cytoplasm	Regulation TLR4 and RLH pathways
High mobility group protein B3	O15347	C-terminal COFRADIC	KKVEEEDE	EEEEEEEEEEEEEDE	0.083	Nucleus/Cytoplasm	Transcription regulation, chromatin
		C-terminal COFRADIC	KKVEEED	EEEEEEEEEEEEEEDE	N/A
High mobility group protein B2	P26583	Western blot		EDEEEEEEEEDEDEEEEDEDEEb		Nucleus/Cytoplasm	Transcription regulation, chromatin
High mobility group protein B1	P09429	Western blot		EEEEDEEDEEDEEEEEDEEDEDEEEDDDDEb		Nucleus/Cytoplasm	Transcription regulation, chromatin
Myosin light chain kinase 1/Telokinc	Q6PDN3	Western blot		EEEEEEd		Cytoplasm	Regulator of myosin function

N/A, not applicable for the impossibility to calculate an m/z ratio due to the absence of light peptide ions (i.e. peptide not identified in the control sample).

^a In the case of α-tubulin, we considered that CCP1 uses as substrate the pool of detyrosinated tubulin naturally present in the cell (15, 38).

^b The C-terminus of these proteins is displayed, although no CCP1 cleavage sites have been identified.

^c This substrate was not identified in our screen, but the orthologous mouse substrate was previously reported by Rogowski et al. (15).

^d Based on western blots showing an increase in Δ2-tubulin.