Pulmonary surfactant-associated protein A1 (PSP-A) (PSPA) (SP-A) (SP-A1) (35 kDa pulmonary surfactant-associated protein) (Alveolar proteinosis protein) (Collectin-4)
1_MWLCP 6_ LALNL 11_ ILMAA 16_ SGAVC 21_ EVKDV 26_ CVGSP 31_ GIPGT 36_ PGSHG 41_ LPGRD 46_ GRDGL 51_ KGDPG 56_ PPGPM 61_ GPPGE 66_ MPCPP 71_ GNDGL 76_ PGAPG 81_ IPGEC 86_ GEKGE 91_ PGERG 96_ PPGLP 101_ AHLDE 106_ ELQAT 111_ LHDFR 116_ HQILQ 121_ TRGAL 126_ SLQGS 131_ IMTVG 136_ EKVFS 141_ SNGQS 146_ ITFDA 151_ IQEAC 156_ ARAGG 161_ RIAVP 166_ RNPEE 171_ NEAIA 176_ SFVKK 181_ YNTYA 186_ YVGLT 191_ EGPSP 196_ GDFRY 201_ SDGTP 206_ VNYTN 211_ WYRGE 216_ PAGRG 221_ KEQCV 226_ EMYTD 231_ GQWND 236_ RNCLY 241_SRLTI
1: In presence of calcium ions, it binds to surfactant phospholipids and contributes to lower the surface tension at the air-liquid interface in the alveoli of the mammalian lung and is essential for normal respiration. Enhances the expression of MYO18A/SP-R210 on alveolar macrophages (By similarity)
2: (Microbial infection) Recognition of M.tuberculosis by dendritic cells may occur partially via this molecule (PubMed:17158455, PubMed:21203928). Can recognize, bind, and opsonize pathogens to enhance their elimination by alveolar macrophages (PubMed:21123169)
3: (Microbial infection) Binds M.pneumoniae CARDS toxin, serves as one receptor for this pathogen (PubMed:15845487, PubMed:25139904). When SFTPA1 is down-regulated by siRNA, less toxin binds to human cells and less vacuolization (a symptom of M.pneumoniae infection) is seen (PubMed:25139904)