Table 2. Hub Proteins of Networks Present Only in Control Exosomes^a.

network cluster	gene name	protein description	# nodes	reported functions in AD or neurodegeneration
ribosomes	RPL4	60S ribosomal protein L4	22	None
	RPL7	60S ribosomal protein L7	17	forms aggregates with tau pathology119
	RPL12	60S ribosomal protein L12	15	associated with AD transcriptional changes120
	RPL13A	6S ribosomal protein L13a	11	None
	RPL18A	60S ribosomal protein L18a	26	None
	R	ribosomal protein L19	24	decreased synthesis in p-tau neurons121
	RPL27A	60S ribosomal protein L27a	16	None
	RPS2	40S ribosomal protein S2	16	None
translation initiation	ElF2S3	eukaryotic translation initiation factor 2 subunit 3	17	None
	ElF3B	eukaryotic translation initiation factor 3 subunit B	10	None
	EIF3J	eukaryotic translation initiation factor 3 subunit J	15	None
phosphatase	PPP2R2A	serine/threonine-protein phosphatase 2A 55 kDa regulatory subunit B α	17	dephosphorylation of p-tau92
RNA binding and processing	SRSF1	serine/arginine-rich-splicing factor 1	17	participates in binding to tau pre-mRNA117
	SRSF7	serine/arginine-rich-splicing factor 7	10	role in regulation of tau RNA alternative splicing118
	FUS	RNA-binding protein FUS	15	mutations in FUS are linked to familial ALS and FTLD96−99,105,106
	HNRNPU	heterogeneous nuclear ribonucleoprotein U	15	None
	PA2G4/EBP1	proliferation-assoc. protein 2G4	14	None
	DHX9	ATP-dependent RNA helicase	12	None
	NUDT21	cleavage and polyadenylation specificity factor subunit 5	12	None
proteasome	PSMC1	26S proteasome regulatory subunit 4	12	None
	PSMC4	26S proteasome regulatory subunit 68	14	dysregulated in AD and accumulates in Lewy bodies in PD122
	PSMD11	26S proteasome non-ATPase regulatory subunit 11	13	None

^aProteins identified only in the control PS1 exosomes are listed by gene name, number of interacting proteins terms “nodes”, and description of protein function. All proteins were identified with FDR less than 1% (see Experimental Procedures).