Regulates clathrin-mediated endocytosis by phosphorylating the AP2M1/mu2 subunit of the adaptor protein complex 2 (AP-2) which ensures high affinity binding of AP-2 to cargo membrane proteins during the initial stages of endocytosis. Preferentially, may phosphorylate substrates on threonine residues. Regulates phosphorylation of other AP-2 subunits as well as AP-2 localization and AP-2-mediated internalization of ligand complexes. Phosphorylates NUMB and regulates its cellular localization, promoting NUMB localization to endosomes. Binds to and stabilizes the activated form of NOTCH1, increases its localization in endosomes and regulates its transcriptional activity. {ECO:0000250|UniProtKB:Q2M2I8}.

Phosphatidylserine (PS) lipase that mediates the hydrolysis of phosphatidylserine to generate lysophosphatidylserine (LPS). LPS constitutes a class of signaling lipids that regulates immunological and neurological processes (By similarity). Has no activity towards diacylglycerol, triacylglycerol or lysophosphatidylserine lipase (By similarity). Also has monoacylglycerol lipase activity, with preference for 1-(9Z,12Z-octadecadienoyl)-glycerol (1-LG) and 2-glyceryl-15-deoxy-Delta(12,14)-prostaglandin J2 (15d-PGJ(2)-G) (By similarity). {ECO:0000250|UniProtKB:O95870, ECO:0000250|UniProtKB:Q9Z1Q2}.

May act in negative regulation of cell growth and transformation by interacting with nonreceptor tyrosine kinases ABL1 and/or ABL2. May play a role in regulation of EGF-induced Erk pathway activation. Involved in cytoskeletal reorganization and EGFR signaling. Together with EPS8 participates in transduction of signals from Ras to Rac. In vitro, a trimeric complex of ABI1, EPS8 and SOS1 exhibits Rac specific guanine nucleotide exchange factor (GEF) activity and ABI1 seems to act as an adapter in the complex. Regulates ABL1/c-Abl-mediated phosphorylation of ENAH. Recruits WASF1 to lamellipodia and there seems to regulate WASF1 protein level. In brain, seems to regulate the dendritic outgrowth and branching as well as to determine the shape and number of synaptic contacts of developing neurons. {ECO:0000269|PubMed:11003655, ECO:0000269|PubMed:18328268}.

Cleaves the membrane-bound precursor of TNF-alpha to its mature soluble form. Responsible for the proteolytical release of soluble JAM3 from endothelial cells surface. Plays a role in the proteolytic processing of ACE2 (By similarity). Responsible for the proteolytic release of several other cell-surface proteins, including p75 TNF-receptor, interleukin 1 receptor type II, p55 TNF-receptor, transforming growth factor-alpha, L-selectin, growth hormone receptor, MUC1 and the amyloid precursor protein (PubMed:10799547, PubMed:11108241). Acts as an activator of Notch pathway by mediating cleavage of Notch, generating the membrane-associated intermediate fragment called notch extracellular truncation (NEXT) (PubMed:10882063). Plays a role in hemostasis through shedding of GP1BA, the platelet glycoprotein Ib alpha chain (PubMed:12907434). Mediates the proteolytic cleavage of LAG3, leading to release the secreted form of LAG3 (PubMed:17245433). Mediates the proteolytic cleavage of IL6R, leading to the release of secreted form of IL6R (By similarity). {ECO:0000250|UniProtKB:P78536, ECO:0000269|PubMed:10799547, ECO:0000269|PubMed:10882063, ECO:0000269|PubMed:11108241, ECO:0000269|PubMed:12907434, ECO:0000269|PubMed:17245433}.

Cleaves the membrane-bound precursor of TNF-alpha to its mature soluble form (PubMed:9034191). Responsible for the proteolytical release of soluble JAM3 from endothelial cells surface (PubMed:20592283). Responsible for the proteolytic release of several other cell-surface proteins, including p75 TNF-receptor, interleukin 1 receptor type II, p55 TNF-receptor, transforming growth factor-alpha, L-selectin, growth hormone receptor, MUC1 and the amyloid precursor protein (PubMed:12441351). Acts as an activator of Notch pathway by mediating cleavage of Notch, generating the membrane-associated intermediate fragment called Notch extracellular truncation (NEXT) (PubMed:24226769). Plays a role in the proteolytic processing of ACE2 (PubMed:24227843). Plays a role in hemostasis through shedding of GP1BA, the platelet glycoprotein Ib alpha chain (By similarity). Mediates the proteolytic cleavage of LAG3, leading to release the secreted form of LAG3 (By similarity). Mediates the proteolytic cleavage of IL6R, leading to the release of secreted form of IL6R (PubMed:26876177, PubMed:28060820). {ECO:0000250|UniProtKB:Q9Z0F8, ECO:0000269|PubMed:12441351, ECO:0000269|PubMed:20592283, ECO:0000269|PubMed:24226769, ECO:0000269|PubMed:24227843, ECO:0000269|PubMed:26876177, ECO:0000269|PubMed:28060820, ECO:0000269|PubMed:9034191}.

Membrane-cytoskeleton-associated protein that promotes the assembly of the spectrin-actin network. Binds to calmodulin.

[Isoform 1]: As a positive regulator of collagen fibrillogenesis, it is probably involved in the organization and remodeling of the extracellular matrix. {ECO:0000250|UniProtKB:Q8IUX7}.; [Isoform 2]: May positively regulate MAP-kinase activity in adipocytes, leading to enhanced adipocyte proliferation and reduced adipocyte differentiation. May also positively regulate NF-kappa-B activity in macrophages by promoting the phosphorylation and subsequent degradation of I-kappa-B-alpha (NFKBIA), leading to enhanced macrophage inflammatory responsiveness. Can act as a transcriptional repressor. {ECO:0000269|PubMed:10406805, ECO:0000269|PubMed:11152475, ECO:0000269|PubMed:11438679, ECO:0000269|PubMed:14729459, ECO:0000269|PubMed:16307171, ECO:0000269|PubMed:16461908, ECO:0000269|PubMed:16538615, ECO:0000269|PubMed:17202411, ECO:0000269|PubMed:7477299}.

Key component of the super elongation complex (SEC), a complex required to increase the catalytic rate of RNA polymerase II transcription by suppressing transient pausing by the polymerase at multiple sites along the DNA. In the SEC complex, AFF4 acts as a central scaffold that recruits other factors through direct interactions with ELL proteins (ELL, ELL2 or ELL3) and the P-TEFb complex. In case of infection by HIV-1 virus, the SEC complex is recruited by the viral Tat protein to stimulate viral gene expression. {ECO:0000269|PubMed:20159561, ECO:0000269|PubMed:20471948, ECO:0000269|PubMed:23251033}.

GTPase-activating protein (GAP) for ARF1 and ARF5, which also shows strong GTPase activity. Participates in the prevention of neuronal apoptosis by enhancing PI3 kinase activity. Aids the coupling of metabotropic glutamate receptor 1 (GRM1) to cytoplasmic PI3 kinase by interacting with Homer scaffolding proteins, and also seems to mediate anti-apoptotic effects of NGF by activating nuclear PI3 kinase (By similarity). {ECO:0000250}.

Required for vesicle docking or fusion during acrosome biogenesis. May play a role in RNA trafficking or localization. {ECO:0000269|PubMed:11711676}.

Required for the assembly of a functional nuclear pore complex (NPC) on the surface of chromosomes as nuclei form at the end of mitosis. May initiate NPC assembly by binding to chromatin and recruiting the Nup107-160 subcomplex of the NPC. Also required for the localization of the Nup107-160 subcomplex of the NPC to the kinetochore during mitosis and for the completion of cytokinesis (By similarity). Has also been proposed to function as a transcription factor which may play a specific role in hematopoietic tissues (PubMed:11952839). {ECO:0000250, ECO:0000269|PubMed:11952839}.

Anchoring protein that mediates the subcellular compartmentation of protein kinase A (PKA) and protein kinase C (PKC). {ECO:0000250}.