Table III. Example of Cx43-interacting proteins identified in this study that were previously reported to be altered in chondrocytes from OA patients (46–53). # Interactors exclusively identified in samples from healthy donors. * Interactors that were only identified in samples from OA patients. The remaining interactors were identified in both samples (healthy and early\moderate OA). Protein Pilot Score, Amino acids sequence coverage for the identified proteins (Cov.) and number of peptides (No. pept.) masses matching\not matching the top hit from MS-Fit PMF. Only proteins that show >95% confidence and score >1.3 were considered for this study.

Group\Complex	Protein name	Gene name	Healthy OA (g. I\III)	Score	Cov.	No. pept.
Extracellular matrix structural constituent	Collagen alpha-1(I) chain	COL1A1	Healthy	6	23.9	3
			OA (g. III)	8.24	50	4
	Collagen alpha-2(I) chain	COL1A2	Healthy	4	31.3	2
			OA (g. III)	2	40.7	1
	Collagen alpha-1(VI) chain*	COL6A1*	OA (g. I\III)	21.28\10.29	57.1\51.3	12\6
	Collagen alpha-2(VI) chain*	COL6A2*	OA (g. I\III)	14.25\6	56.1\36.3	11\4
	Collagen alpha-3(IV) chain*	COL6A3*	Healthy	2.84	7.4	2
			OA (g. I\III)	95.44\61.62	53.9\47.5	54\34
	Collagen alpha-1(XII) chain*	COL12A1*	OA (g. I\III)	23.48\14.16	41.2\32.6	11\8
Carbohydrate metabolic processes	Alpha-enolase	ENO1	Healthy	8	21	4
			OA (g. I\III)	26.89\26.98	65\58.1	13\14
	Glyceraldehyde-3-phosphate dehydrogenase	GAPDH	Healthy	10.41	30.5	5
			OA (g. I\III)	4.04\9.96	42.4\31.6	2\5
	Fructose-biphosphate aldolase A	ALDOA	Healthy	2.01	8.8	1
			OA (g. I\III)	2.1\7.56	43.7\38.5	1\4
Cytoskeleton related-proteins	Vimentin	VIM	Healthy	81.76	87.1	48
			OA (g. I\III)	124.3\78.96	100\94.2	158\53
	Gelsolin	GSN	Healthy	2	6.8	1
			OA (g. I\III)	2\9.81	17.4\39.1	1\5
	Vinculin	VCL	Healthy	5.29	20.3	3
			OA (g. I\III)	4.32\13.21	40.5\45.3	2\7
	Actin, cytoplasmic 1	ACTB	Healthy	25.29	53.6	16
			OA (g. III)	29.04	62.9	21
	Erzin	EZR1#	Healthy	2	3.9	1
	Moesin	MSN	Healthy	10.09	29.5	5
			OA (g. I\III)	10.02\12.35	59.1\53	6\7
Chaperone and Protein folding-related proteins	Alpha-crystallin B chain	CRYAB	Healthy	4	26.3	2
			OA (g. I\III)	13.73\4.18	65.7\47.4	7\2
	Heat shock cognate 71 KDa protein	HSPA8	Healthy	10.72	22.5	5
			OA (g. I\III)	3.04\13.06	35.8\42.9	2\8
	Heat shock protein HSP 90-beta	HSP90AB1	Healthy	7.26	17.4	4
			OA (g. I\III)	2.81\16.29	28\34.7	2\8
	Endoplasmin	HSP90B1	Healthy	5.64	5.6	3
			OA (g. I\III)	3.82\22.57	31.1\38.5	2\11
	78 kDa glucose-regulated protein	HSPA5	Healthy	22.93	30.3	11
			OA (g. I\III)	6.14\32.82	53.4\60.6	3\17
Others	Annexin A1	ANXA1	Healthy	10	30.6	5
			OA (g. I\III)	10.87\6.15	47.4\27.2	6\3
	Annexin A2	ANXA2	Healthy	52.03	65.8	30
			OA (g. I\III)	54.59\48.92	84.4\86.1	40\30
	Annexin A5	ANXA5	Healthy	2	19.7	1
			OA (g. I\III)	2.05\2	32.8\20.6	1\1
	Superoxide dismutase [Mn], mitochondrial	SOD2#	Healthy	2	15.3	1
	Prelamin-A\C	LMNA	Healthy	26.38	44.7	15
			OA (g. I\III)	39.97\16.48	82.7\55.1	21\8
	Eukaryotic translation initation factor 5A-2	EIF5A2	OA (g. I)	2	40.5	1
	Elongation factor 2	EEF2	Healthy	14.35	21.1	7
			OA (g. I)	9.2\19.24	35.9\34.4	5\9
	Dihydropyrimidinase-related protein 2	DPYSL2	Healthy	2.37	18.9	1
			OA (g. III)	7.31	35.1	4
	Major vault protein	MVP	Healthy	2	3.9	1
			OA (g. III)	2.3	31	1
	GTP-binding nuclear protein RAN	RAN	Healthy	4	11.6	2
			OA (g. I)	2.01	34.7	1
	Integrin alpha-V	ITGAV*	OA (g. I)	2.03	20.9	1
	Integrin beta-1	ITGB1*	OA (g. I\III)	2\2	18.9\8.4	1\1