Theheparansulphateproteoglycanagriniswellknownasthekeyassemblyfactorofpostsynapticdifferentiationattheneuromuscularjunction(NMJ),butrecentdatasuggestitalsoplaysadirectroleintheorganizationoftheCytoskeletonintheskeletalmuscle.Signalingthroughmuscle-specificproteinssuchasmusclespecifickinase(MuSK)andoracetylcholinereceptor(AchRs)/rapsyn,agrincanactivateubiquitouslyexpressedRac,Cdc42,andp21-activatedkinase(PAK)thatareinvolvedinactinpolymerization.Agrinalsoengagessignalingpathwaysofseveralpotentoncogenes(i.e.,SFK,ErbBreceptors,andcortactin). Contributor:KosiGramatikoff,PhD REFERENCES:BezakovaG,RueggMA.Newinsightsintotherolesofagrin.NatRevMolCellBiol.2003Apr;4(4):295-308.MollJetal.Anagrinminigenerescuesdystrophicsymptomsinamousemodelforcongenitalmusculardystrophy.Nature.2001Sep20;413(6853):302-7.