Homer protein homolog 1 (Homer-1)
1_MGEQP 6_ IFSTR 11_ AHVFQ 16_ IDPNT 21_ KKNWV 26_ PTSKH 31_ AVTVS 36_ YFYDS 41_ TRNVY 46_ RIISL 51_ DGSKA 56_ IINST 61_ ITPNM 66_ TFTKT 71_ SQKFG 76_ QWADS 81_ RANTV 86_ YGLGF 91_ SSEHH 96_ LSKFA 101_ EKFQE 106_ FKEAA 111_ RLAKE 116_ KSQEK 121_ MELTS 126_ TPSQE 131_ SAGGD 136_ LQSPL 141_ TPESI 146_ NGTDD 151_ ERTPD 156_ VTQNS 161_ EPRAE 166_ PTQNA 171_ LPFSH 176_ SSAIS 181_ KHWEA 186_ ELATL 191_ KGNNA 196_ KLTAA 201_ LLEST 206_ ANVKQ 211_ WKQQL 216_ AAYQE 221_ EAERL 226_ HKRVT 231_ ELECV 236_ SSQAN 241_ AVHTH 246_ KTELN 251_ QTIQE 256_ LEETL 261_ KLKEE 266_ EIERL 271_ KQEID 276_ NAREL 281_ QEQRD 286_ SLTQK 291_ LQEVE 296_ IRNKD 301_ LEGQL 306_ SDLEQ 311_ RLEKS 316_ QNEQE 321_ AFRNN 326_ LKTLL 331_ EILDG 336_ KIFEL 341_ TELRD 346_NLAKL
1: Postsynaptic density scaffolding protein. Binds and cross-links cytoplasmic regions of GRM1, GRM5, ITPR1, DNM3, RYR1, RYR2, SHANK1 and SHANK3. By physically linking GRM1 and GRM5 with ER-associated ITPR1 receptors, it aids the coupling of surface receptors to intracellular calcium release. May also couple GRM1 to PI3 kinase through its interaction with AGAP2. Isoform 1 regulates the trafficking and surface expression of GRM5. Isoform 3 acts as a natural dominant negative, in dynamic competition with constitutively expressed isoform 1 to regulate synaptic metabotropic glutamate function. Isoform 3, may be involved in the structural changes that occur at synapses during long-lasting neuronal plasticity and development. Forms a high-order complex with SHANK1, which in turn is necessary for the structural and functional integrity of dendritic spines (By similarity). Negatively regulates T cell activation by inhibiting the calcineurin-NFAT pathway. Acts by competing with calcineurin/PPP3CA for NFAT protein binding, hence preventing NFAT activation by PPP3CA (PubMed:18218901)